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1 hd44780u (lcd-ii) (dot matrix liquid crystal display controller/driver) description the hd44780u dot-matrix liquid crystal display controller and driver lsi displays alphanumerics, japanese kana characters, and symbols. it can be configured to drive a dot-matrix liquid crystal display under the control of a 4- or 8-bit microprocessor. since all the functions such as display ram, character generator, and liquid crystal driver, required for driving a dot-matrix liquid crystal display are internally provided on one chip, a minimal system can be interfaced with this controller/driver. a single hd44780u can display up to one 8-character line or two 8-character lines. the hd44780u has pin function compatibility with the hd44780s which allows the user to easily replace an lcd-ii with an hd44780u. the hd44780u character generator rom is extended to generate 208 5 8 dot character fonts and 32 5 10 dot character fonts for a total of 240 different character fonts. the low power supply (2.7v to 5.5v) of the hd44780u is suitable for any portable battery-driven product requiring low power dissipation. features 5 8 and 5 10 dot matrix possible low power operation support: ? 2.7 to 5.5v wide range of liquid crystal display driver power ? 3.0 to 11v liquid crystal drive waveform ? a (one line frequency ac waveform) correspond to high speed mpu bus interface ? 2 mhz (when v cc = 5v) 4-bit or 8-bit mpu interface enabled 80 8-bit display ram (80 characters max.) 9,920-bit character generator rom for a total of 240 character fonts ? 208 character fonts (5 8 dot) ? 32 character fonts (5 10 dot)
hd44780u 2 64 8-bit character generator ram ? 8 character fonts (5 8 dot) ? 4 character fonts (5 10 dot) 16-common 40-segment liquid crystal display driver programmable duty cycles ? 1/8 for one line of 5 8 dots with cursor ? 1/11 for one line of 5 10 dots with cursor ? 1/16 for two lines of 5 8 dots with cursor wide range of instruction functions: ? display clear, cursor home, display on/off, cursor on/off, display character blink, cursor shift, display shift pin function compatibility with hd44780s automatic reset circuit that initializes the controller/driver after power on internal oscillator with external resistors low power consumption ordering information type no. package cgrom hd44780ua00fs HCD44780UA00 hd44780ua00tf fp-80b chip tfp-80f japanese standard font hd44780ua02fs hcd44780ua02 hd44780ua02tf fp-80b chip tfp-80f european standard font hd44780ubxxfs hcd44780ubxx hd44780ubxxtf fp-80b chip tfp-80f custom font note: xx: rom code no.
hd44780u 3 hd44780u block diagram display data ram (ddram) 80 8 bits character generator rom (cgrom) 9,920 bits character generator ram (cgram) 64 bytes instruction register (ir) timing generator common signal driver 16-bit shift register segment signal driver 40-bit latch circuit 40-bit shift register parallel/serial converter and attribute circuit lcd drive voltage selector address counter mpu inter- face input/ output buffer data register (dr) cursor and blink controller cpg cl1 cl2 m d rs r/w db4 to db7 e instruction decoder osc1 osc2 com1 to com16 seg1 to seg40 8 8 8 7 40 5 5 7 8 7 8 7 v cc gnd v1 v2 v3 v4 v5 db0 to db3 reset circuit acl 8 busy flag
hd44780u 4 hd44780u pin arrangement (fp-80b) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 fp-80b (top view) seg39 seg40 com16 com15 com14 com13 com12 com11 com10 com9 com8 com7 com6 com5 com4 com3 com2 com1 db7 db6 db5 db4 db3 db2 seg22 seg21 seg20 seg19 seg18 seg17 seg16 seg15 seg14 seg13 seg12 seg11 seg10 seg9 seg8 seg7 seg6 seg5 seg4 seg3 seg2 seg1 gnd osc1 seg23 seg24 seg25 seg26 seg27 seg28 seg29 seg30 seg31 seg32 seg33 seg34 seg35 seg36 seg37 osc2 v1 v2 v3 v4 v5 cl1 cl2 v cc m d rs r/w e db0 db1 seg38
hd44780u 5 hd44780u pin arrangement (tfp-80f) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 tfp-80f (top view) com16 com15 com14 com13 com12 com11 com10 com9 com8 com7 com6 com5 com4 com3 com2 com1 db7 db6 db5 db4 seg20 seg19 seg18 seg17 seg16 seg15 seg14 seg13 seg12 seg11 seg10 seg9 seg8 seg7 seg6 seg5 seg4 seg3 seg2 seg1 seg21 seg22 seg23 seg24 seg25 seg26 seg27 seg28 seg29 seg30 seg31 seg32 seg33 seg34 seg35 seg36 seg37 seg38 seg39 seg40 gnd osc1 osc2 v1 v2 v3 v4 v5 cl1 cl2 v cc m d rs r/w e db0 db1 db2 db3
hd44780u 6 hd44780u pad arrangement hd44780u type code 23 x y 42 2 1 80 63 chip size: coordinate: origin: pad size: 4.90 4.90 mm 2 pad center ( m) chip center 114 114 m 2
hd44780u 7 hcd44780u pad location coordinates coordinate coordinate pad no. function x (um) y (um) pad no. function x (um) y (um) 1 seg22 ?100 2313 41 db2 2070 ?290 2 seg21 ?280 2313 42 db3 2260 ?290 3 seg20 ?313 2089 43 db4 2290 ?099 4 seg19 ?313 1833 44 db5 2290 ?883 5 seg18 ?313 1617 45 db6 2290 ?667 6 seg17 ?313 1401 46 db7 2290 ?452 7 seg16 ?313 1186 47 com1 2313 ?186 8 seg15 ?313 970 48 com2 2313 ?70 9 seg14 ?313 755 49 com3 2313 ?55 10 seg13 ?313 539 50 com4 2313 ?39 11 seg12 ?313 323 51 com5 2313 ?23 12 seg11 ?313 108 52 com6 2313 ?08 13 seg10 ?313 ?08 53 com7 2313 108 14 seg9 ?313 ?23 54 com8 2313 323 15 seg8 ?313 ?39 55 com9 2313 539 16 seg7 ?313 ?55 56 com10 2313 755 17 seg6 ?313 ?70 57 com11 2313 970 18 seg5 ?313 ?186 58 com12 2313 1186 19 seg4 ?313 ?401 59 com13 2313 1401 20 seg3 ?313 ?617 60 com14 2313 1617 21 seg2 ?313 ?833 61 com15 2313 1833 22 seg1 ?313 ?073 62 com16 2313 2095 23 gnd ?280 ?290 63 seg40 2296 2313 24 osc1 ?080 ?290 64 seg39 2100 2313 25 osc2 ?749 ?290 65 seg38 1617 2313 26 v1 ?550 ?290 66 seg37 1401 2313 27 v2 ?268 ?290 67 seg36 1186 2313 28 v3 ?41 ?290 68 seg35 970 2313 29 v4 ?23 ?290 69 seg34 755 2313 30 v5 ?04 ?290 70 seg33 539 2313 31 cl1 ?8 ?290 71 seg32 323 2313 32 cl2 142 ?290 72 seg31 108 2313 33 v cc 309 ?290 73 seg30 ?08 2313 34 m 475 ?290 74 seg29 ?23 2313 35 d 665 ?290 75 seg28 ?39 2313 36 rs 832 ?290 76 seg27 ?55 2313 37 r/ w 1022 ?290 77 seg26 ?70 2313 38 e 1204 ?290 78 seg25 ?186 2313 39 db0 1454 ?290 79 seg24 ?401 2313 40 db1 1684 ?290 80 seg23 ?617 2313
hd44780u 8 pin functions signal no. of lines i/o device interfaced with function rs 1 i mpu selects registers. 0: instruction register (for write) busy flag: address counter (for read) 1: data register (for write and read) r/ w 1 i mpu selects read or write. 0: write 1: read e 1 i mpu starts data read/write. db4 to db7 4 i/o mpu four high order bidirectional tristate data bus pins. used for data transfer and receive between the mpu and the hd44780u. db7 can be used as a busy flag. db0 to db3 4 i/o mpu four low order bidirectional tristate data bus pins. used for data transfer and receive between the mpu and the hd44780u. these pins are not used during 4-bit operation. cl1 1 o extension driver clock to latch serial data d sent to the extension driver cl2 1 o extension driver clock to shift serial data d m 1 o extension driver switch signal for converting the liquid crystal drive waveform to ac d 1 o extension driver character pattern data corresponding to each segment signal com1 to com16 16 o lcd common signals that are not used are changed to non-selection waveforms. com9 to com16 are non-selection waveforms at 1/8 duty factor and com12 to com16 are non-selection waveforms at 1/11 duty factor. seg1 to seg40 40 o lcd segment signals v1 to v5 5 power supply power supply for lcd drive v cc ?5 = 11 v (max) v cc , gnd 2 power supply v cc : 2.7v to 5.5v, gnd: 0v osc1, osc2 2 oscillation resistor clock when crystal oscillation is performed, a resistor must be connected externally. when the pin input is an external clock, it must be input to osc1.
hd44780u 9 function description registers the hd44780u has two 8-bit registers, an instruction register (ir) and a data register (dr). the ir stores instruction codes, such as display clear and cursor shift, and address information for display data ram (ddram) and character generator ram (cgram). the ir can only be written from the mpu. the dr temporarily stores data to be written into ddram or cgram and temporarily stores data to be read from ddram or cgram. data written into the dr from the mpu is automatically written into ddram or cgram by an internal operation. the dr is also used for data storage when reading data from ddram or cgram. when address information is written into the ir, data is read and then stored into the dr from ddram or cgram by an internal operation. data transfer between the mpu is then completed when the mpu reads the dr. after the read, data in ddram or cgram at the next address is sent to the dr for the next read from the mpu. by the register selector (rs) signal, these two registers can be selected (table 1). busy flag (bf) when the busy flag is 1, the hd44780u is in the internal operation mode, and the next instruction will not be accepted. when rs = 0 and r/ w = 1 (table 1), the busy flag is output to db7. the next instruction must be written after ensuring that the busy flag is 0. address counter (ac) the address counter (ac) assigns addresses to both ddram and cgram. when an address of an instruction is written into the ir, the address information is sent from the ir to the ac. selection of either ddram or cgram is also determined concurrently by the instruction. after writing into (reading from) ddram or cgram, the ac is automatically incremented by 1 (decremented by 1). the ac contents are then output to db0 to db6 when rs = 0 and r/ w = 1 (table 1). table 1 register selection rs r/ w operation 0 0 ir write as an internal operation (display clear, etc.) 0 1 read busy flag (db7) and address counter (db0 to db6) 1 0 dr write as an internal operation (dr to ddram or cgram) 1 1 dr read as an internal operation (ddram or cgram to dr)
hd44780u 10 display data ram (ddram) display data ram (ddram) stores display data represented in 8-bit character codes. its extended capacity is 80 8 bits, or 80 characters. the area in display data ram (ddram) that is not used for display can be used as general data ram. see figure 1 for the relationships between ddram addresses and positions on the liquid crystal display. the ddram address (a dd ) is set in the address counter (ac) as hexadecimal. 1-line display (n = 0) (figure 2) ? when there are fewer than 80 display characters, the display begins at the head position. for example, if using only the hd44780, 8 characters are displayed. see figure 3. when the display shift operation is performed, the ddram address shifts. see figure 3. ac6 ac5 ac4 ac3 ac2 ac1 ac0 1001110 ac (hexadecimal) example: ddram address 4e high order bits low order bits figure 1 ddram address 00 01 02 03 04 4e 4f ddram address (hexadecimal) display position (digit) 123 45 7980 . . . . . . . . . . . . . . . . . . figure 2 1-line display ddram address display position 12345 678 00 01 02 03 04 05 06 07 for shift left for shift right 00 01 02 03 04 05 06 01 02 03 04 05 06 07 08 4f figure 3 1-line by 8-character display example
hd44780u 11 2-line display (n = 1) (figure 4) ? case 1: when the number of display characters is less than 40 2 lines, the two lines are displayed from the head. note that the first line end address and the second line start address are not consecutive. for example, when just the hd44780 is used, 8 characters 2 lines are displayed. see figure 5. when display shift operation is performed, the ddram address shifts. see figure 5. 00 01 02 03 04 26 27 ddram address (hexadecimal) display position 123 45 3940 . . . . . . . . . . . . . . . . . . 40 41 42 43 44 66 67 . . . . . . . . . . . . . . . . . . figure 4 2-line display ddram address display position 12345 678 00 01 02 03 04 05 06 07 for shift left for shift right 40 41 42 43 44 45 46 47 01 02 03 04 05 06 07 08 41 42 43 44 45 46 47 48 00 01 02 03 04 05 06 40 41 42 43 44 45 46 27 67 figure 5 2-line by 8-character display example
hd44780u 12 ? case 2: for a 16-character 2-line display, the hd44780 can be extended using one 40-output extension driver. see figure 6. when display shift operation is performed, the ddram address shifts. see figure 6. ddram address display position 1 2345678910111213141516 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f for shift left 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 27 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f hd44780u display extension driver display 02 01 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 for shift right 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f 50 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 67 figure 6 2-line by 16-character display example
hd44780u 13 character generator rom (cgrom) the character generator rom generates 5 8 dot or 5 10 dot character patterns from 8-bit character codes (table 4). it can generate 208 5 8 dot character patterns and 32 5 10 dot character patterns. user- defined character patterns are also available by mask-programmed rom. character generator ram (cgram) in the character generator ram, the user can rewrite character patterns by program. for 5 8 dots, eight character patterns can be written, and for 5 10 dots, four character patterns can be written. write into ddram the character codes at the addresses shown as the left column of table 4 to show the character patterns stored in cgram. see table 5 for the relationship between cgram addresses and data and display patterns. areas that are not used for display can be used as general data ram. modifying character patterns character pattern development procedure the following operations correspond to the numbers listed in figure 7: 1. determine the correspondence between character codes and character patterns. 2. create a listing indicating the correspondence between eprom addresses and data. 3. program the character patterns into the eprom. 4. send the eprom to hitachi. 5. computer processing on the eprom is performed at hitachi to create a character pattern listing, which is sent to the user. 6. if there are no problems within the character pattern listing, a trial lsi is created at hitachi and samples are sent to the user for evaluation. when it is confirmed by the user that the character patterns are correctly written, mass production of the lsi proceeds at hitachi.
hd44780u 14 determine character patterns create eprom address data listing write eprom eprom ? hitachi computer processing create character pattern listing evaluate character patterns ok? art work sample evaluation ok? masking trial sample no yes no yes m/t 1 3 2 4 5 6 note: for a description of the numbers used in this figure, refer to the preceding page. user hitachi mass production start figure 7 character pattern development procedure
hd44780u 15 programming character patterns this section explains the correspondence between addresses and data used to program character patterns in eprom. the hd44780u character generator rom can generate 208 5 8 dot character patterns and 32 5 10 dot character patterns for a total of 240 different character patterns. ? character patterns eprom address data and character pattern data correspond with each other to form a 5 8 or 5 10 dot character pattern (tables 2 and 3). table 2 example of correspondence between eprom address data and character pattern (5 8 dots) data o4 o3 o2 o1 o0 0 0 0 1 0 0 1 0 0 0 1 1 0 1 0 0 0 1 1 0 0 0 1 0 eprom address character code line position lsb 0 1 0 1 0 1 1 0 0 1 1 1 0 0 0 0 1 0 0 1 1 0 1 0 1 0 1 1 1 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1 1 0 0 0 1 1 0 0 1 1 0 0 0 1 1 0 0 0 1 1 0 0 0 0 1 0 0 0 0 1 0 1 1 0 cursor position 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 a10 a9 a8 a7 a6 a5 a4 a3 a2 a1 a0 a11 notes: 1. eprom addresses a11 to a4 correspond to a character code. 2. eprom addresses a3 to a0 specify a line position of the character pattern. 3. eprom data o4 to o0 correspond to character pattern data. 4. eprom data o5 to o7 must be specified as 0. 5. a lit display position (black) corresponds to a 1. 6. line 9 and the following lines must be blanked with 0s for a 5 8 dot character fonts.
hd44780u 16 ? handling unused character patterns 1. eprom data outside the character pattern area: always input 0s. 2. eprom data in cgram area: always input 0s. (input 0s to eprom addresses 00h to ffh.) 3. eprom data used when the user does not use any hd44780u character pattern: according to the user application, handled in one of the two ways listed as follows. a. when unused character patterns are not programmed: if an unused character code is written into ddram, all its dots are lit. by not programing a character pattern, all of its bits become lit. (this is due to the eprom being filled with 1s after it is erased.) b. when unused character patterns are programmed as 0s: nothing is displayed even if unused character codes are written into ddram. (this is equivalent to a space.) table 3 example of correspondence between eprom address data and character pattern (5 10 dots) a10 a9 a8 a7 a6 a5 a4 a3 a2 a1 a0 data o4 o3 o2 o1 o0 0 0 0 1 0 0 1 0 0 0 1 1 0 1 0 0 0 1 0 1 0 0 1 0 eprom address character code line position lsb 0 1 0 1 0 1 1 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1 1 0 0 1 1 1 0 0 0 1 1 0 0 0 1 0 0 0 0 a11 1 0 0 1 1 0 1 0 1 0 1 1 1 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1 1 0 0 0 cursor position 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 1 1 1 1 notes: 1. eprom addresses a11 to a3 correspond to a character code. 2. eprom addresses a3 to a0 specify a line position of the character pattern. 3. eprom data o4 to o0 correspond to character pattern data. 4. eprom data o5 to o7 must be specified as 0. 5. a lit display position (black) corresponds to a 1. 6. line 11 and the following lines must be blanked with 0s for a 5 10 dot character fonts.
hd44780u 17 table 4 correspondence between character codes and character patterns (rom code: a00) xxxx0000 xxxx0001 xxxx0010 xxxx0011 xxxx0100 xxxx0101 xxxx0110 xxxx0111 xxxx1000 xxxx1001 xxxx1010 xxxx1011 xxxx1100 xxxx1101 xxxx1110 xxxx1111 0000 0010 0011 0100 0101 0110 0111 1010 1011 1100 1101 1110 1111 upper 4 bits lower 4 bits cg ram (1) (2) (3) (4) (5) (6) (7) (8) (1) (2) (3) (4) (5) (6) (7) (8) 0001 1000 1001 note: the user can specify any pattern for character-generator ram.
hd44780u 18 table 4 correspondence between character codes and character patterns (rom code: a02) xxxx0000 xxxx0001 xxxx0010 xxxx0011 xxxx0100 xxxx0101 xxxx0110 xxxx0111 xxxx1000 xxxx1001 xxxx1010 xxxx1011 xxxx1100 xxxx1101 xxxx1110 xxxx1111 0000 0010 0011 0100 0101 0110 0111 1010 1011 1100 1101 1110 1111 upper 4 bits lower 4 bits cg ram (1) (2) (3) (4) (5) (6) (7) (8) (1) (2) (3) (4) (5) (6) (7) (8) 0001 1000 1001
hd44780u 19 table 5 relationship between cgram addresses, character codes (ddram) and character patterns (cgram data) character codes (ddram data) cgram address character patterns (cgram data) 76543210 0000 * 000 0000 * 001 0000 * 111 543210 000 001 111 76543210 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 * * * * * * * * * * * * * * * * * * high low high low high low character pattern (1) cursor position 1 1 1 1 1 1 1 0 1 0 1 0 1 0 0 0 0 1 1 0 0 0 1 0 1 0 1 0 1 0 0 0 1 0 0 1 0 0 0 0 0 1 1 0 1 0 0 0 1 0 0 1 1 0 0 0 0 0 1 1 1 1 1 0 1 0 0 1 0 1 0 0 0 1 1 0 1 0 0 0 character pattern (2) cursor position for 5 8 dot character patterns notes: 1. character code bits 0 to 2 correspond to cgram address bits 3 to 5 (3 bits: 8 types). 2. cgram address bits 0 to 2 designate the character pattern line position. the 8th line is the cursor position and its display is formed by a logical or with the cursor. maintain the 8th line data, corresponding to the cursor display position, at 0 as the cursor display. if the 8th line data is 1, 1 bits will light up the 8th line regardless of the cursor presence. 3. character pattern row positions correspond to cgram data bits 0 to 4 (bit 4 being at the left). 4. as shown table 5, cgram character patterns are selected when character code bits 4 to 7 are all 0. however, since character code bit 3 has no effect, the r display example above can be selected by either character code 00h or 08h. 5. 1 for cgram data corresponds to display selection and 0 to non-selection. * indicates no effect.
hd44780u 20 table 5 relationship between cgram addresses, character codes (ddram) and character patterns (cgram data) (cont) character codes (ddram data) cgram address character patterns (cgram data) 76543210 0000 * 00 0000 11 543210 00 11 76543210 * * * * * * * * * * * * * * * * * * * * * * * * high low high low high low character pattern cursor position 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 * * * * * ** 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 0 0 1 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 1 1 1 0 0 0 0 0 * * * * * * * * * * * * * * * * for 5 10 dot character patterns notes: 1. character code bits 1 and 2 correspond to cgram address bits 4 and 5 (2 bits: 4 types). 2. cgram address bits 0 to 3 designate the character pattern line position. the 11th line is the cursor position and its display is formed by a logical or with the cursor. maintain the 11th line data corresponding to the cursor display positon at 0 as the cursor display. if the 11th line data is ?? ??bits will light up the 11th line regardless of the cursor presence. since lines 12 to 16 are not used for display, they can be used for general data ram. 3. character pattern row positions are the same as 5 8 dot character pattern positions. 4. cgram character patterns are selected when character code bits 4 to 7 are all 0. however, since character code bits 0 and 3 have no effect, the p display example above can be selected by character codes 00h, 01h, 08h, and 09h. 5. 1 for cgram data corresponds to display selection and 0 to non-selection. * indicates no effect.
hd44780u 21 timing generation circuit the timing generation circuit generates timing signals for the operation of internal circuits such as ddram, cgrom and cgram. ram read timing for display and internal operation timing by mpu access are generated separately to avoid interfering with each other. therefore, when writing data to ddram, for example, there will be no undesirable interferences, such as flickering, in areas other than the display area. liquid crystal display driver circuit the liquid crystal display driver circuit consists of 16 common signal drivers and 40 segment signal drivers. when the character font and number of lines are selected by a program, the required common signal drivers automatically output drive waveforms, while the other common signal drivers continue to output non-selection waveforms. sending serial data always starts at the display data character pattern corresponding to the last address of the display data ram (ddram). since serial data is latched when the display data character pattern corresponding to the starting address enters the internal shift register, the hd44780u drives from the head display. cursor/blink control circuit the cursor/blink control circuit generates the cursor or character blinking. the cursor or the blinking will appear with the digit located at the display data ram (ddram) address set in the address counter (ac). for example (figure 8), when the address counter is 08h, the cursor position is displayed at ddram address 08h. ac6 0 ac5 0 ac4 0 ac3 1 ac2 0 ac1 0 ac0 0 1 00 2 01 3 02 4 03 5 04 6 05 7 06 8 07 9 08 10 09 11 0a 1 00 40 2 01 41 3 02 42 4 03 43 5 04 44 6 05 45 7 06 46 8 07 47 9 08 48 10 09 49 11 0a 4a ac cursor position cursor position display position ddram address (hexadecimal) display position ddram address (hexadecimal) for a 1-line display for a 2-line display note: the cursor or blinking appears when the address counter (ac) selects the character generator ram (cgram). however, the cursor and blinking become meaningless. the cursor or blinking is displayed in the meaningless position when the ac is a cgram address. figure 8 cursor/blink display example
hd44780u 22 interfacing to the mpu the hd44780u can send data in either two 4-bit operations or one 8-bit operation, thus allowing interfacing with 4- or 8-bit mpus. for 4-bit interface data, only four bus lines (db4 to db7) are used for transfer. bus lines db0 to db3 are disabled. the data transfer between the hd44780u and the mpu is completed after the 4-bit data has been transferred twice. as for the order of data transfer, the four high order bits (for 8-bit operation, db4 to db7) are transferred before the four low order bits (for 8-bit operation, db0 to db3). the busy flag must be checked (one instruction) after the 4-bit data has been transferred twice. two more 4-bit operations then transfer the busy flag and address counter data. for 8-bit interface data, all eight bus lines (db0 to db7) are used. rs r/w e ir7 ir6 ir5 ir4 bf ac6 ac5 ac4 db7 db6 db5 db4 instruction register (ir) write busy flag (bf) and address counter (ac) read data register (dr) read ir3 ir2 ir1 ir0 ac3 ac2 ac1 ac0 dr7 dr6 dr5 dr4 dr3 dr2 dr1 dr0 figure 9 4-bit transfer example
hd44780u 23 reset function initializing by internal reset circuit an internal reset circuit automatically initializes the hd44780u when the power is turned on. the following instructions are executed during the initialization. the busy flag (bf) is kept in the busy state until the initialization ends (bf = 1). the busy state lasts for 10 ms after v cc rises to 4.5 v. 1. display clear 2. function set: dl = 1; 8-bit interface data n = 0; 1-line display f = 0; 5 8 dot character font 3. display on/off control: d = 0; display off c = 0; cursor off b = 0; blinking off 4. entry mode set: i/d = 1; increment by 1 s = 0; no shift note: if the electrical characteristics conditions listed under the table power supply conditions using internal reset circuit are not met, the internal reset circuit will not operate normally and will fail to initialize the hd44780u. for such a case, initial-ization must be performed by the mpu as explained in the section, initializing by instruction. instructions outline only the instruction register (ir) and the data register (dr) of the hd44780u can be controlled by the mpu. before starting the internal operation of the hd44780u, control information is temporarily stored into these registers to allow interfacing with various mpus, which operate at different speeds, or various peripheral control devices. the internal operation of the hd44780u is determined by signals sent from the mpu. these signals, which include register selection signal (rs), read/ write signal (r/ w ), and the data bus (db0 to db7), make up the hd44780u instructions (table 6). there are four categories of instructions that: designate hd44780u functions, such as display format, data length, etc. set internal ram addresses perform data transfer with internal ram perform miscellaneous functions
hd44780u 24 normally, instructions that perform data transfer with internal ram are used the most. however, auto- incrementation by 1 (or auto-decrementation by 1) of internal hd44780u ram addresses after each data write can lighten the program load of the mpu. since the display shift instruction (table 11) can perform concurrently with display data write, the user can minimize system development time with maximum programming efficiency. when an instruction is being executed for internal operation, no instruction other than the busy flag/address read instruction can be executed. because the busy flag is set to 1 while an instruction is being executed, check it to make sure it is 0 before sending another instruction from the mpu. note: be sure the hd44780u is not in the busy state (bf = 0) before sending an instruction from the mpu to the hd44780u. if an instruction is sent without checking the busy flag, the time between the first instruction and next instruction will take much longer than the instruction time itself. refer to table 6 for the list of each instruc-tion execution time. table 6 instructions code execution time (max) (when f cp or instruction rs r/ w db7 db6 db5 db4 db3 db2 db1 db0 description f osc is 270 khz) clear display 0000 0000 01 clears entire display and sets ddram address 0 in address counter. return home 0000 0000 1 sets ddram address 0 in address counter. also returns display from being shifted to original position. ddram contents remain unchanged. 1.52 ms entry mode set 0000 0001 i/ds sets cursor move direction and specifies display shift. these operations are performed during data write and read. 37 m s display on/off control 0000 001dcb sets entire display (d) on/off, cursor on/off (c), and blinking of cursor position character (b). 37 m s cursor or display shift 0 0 0 0 0 1 s/c r/l moves cursor and shifts display without changing ddram contents. 37 m s function set 0 0 0 0 1 dl n f sets interface data length (dl), number of display lines (n), and character font (f). 37 m s set cgram address 0 0 0 1 acg acg acg acg acg acg sets cgram address. cgram data is sent and received after this setting. 37 m s set ddram address 0 0 1 add add add add add add add sets ddram address. ddram data is sent and received after this setting. 37 m s read busy flag & address 0 1 bf ac ac ac ac ac ac ac reads busy flag (bf) indicating internal operation is being performed and reads address counter contents. 0 m s
hd44780u 25 table 6 instructions (cont) code execution time (max) (when f cp or instruction rs r/ w db7 db6 db5 db4 db3 db2 db1 db0 description f osc is 270 khz) write data to cg or ddram 1 0 write data writes data into ddram or cgram. 37 m s t add = 4 m s* read data from cg or ddram 1 1 read data reads data from ddram or cgram. 37 m s t add = 4 m s* i/d = 1: increment i/d = 0: decrement s = 1: accompanies display shift s/c = 1: display shift s/c = 0: cursor move r/l = 1: shift to the right r/l = 0: shift to the left dl = 1: 8 bits, dl = 0: 4 bits n = 1: 2 lines, n = 0: 1 line f = 1: 5 10 dots, f = 0: 5 8 dots bf = 1: internally operating bf = 0: instructions acceptable ddram: display data ram cgram: character generator ram acg: cgram address add: ddram address (corresponds to cursor address) ac: address counter used for both dd and cgram addresses execution time changes when frequency changes example: when f cp or f osc is 250 khz, 37 s = 40 s 270 250 note: ? indicates no effect. * after execution of the cgram/ddram data write or read instruction, the ram address counter is incremented or decremented by 1. the ram address counter is updated after the busy flag turns off. in figure 10, t add is the time elapsed after the busy flag turns off until the address counter is updated. busy state busy signal (db7 pin) address counter (db0 to db6 pins) t add a a + 1 note: t depends on the operation frequency t = 1.5/(f or f ) seconds add add cp osc figure 10 address counter update
hd44780u 26 instruction description clear display clear display writes space code 20h (character pattern for character code 20h must be a blank pattern) into all ddram addresses. it then sets ddram address 0 into the address counter, and returns the display to its original status if it was shifted. in other words, the display disappears and the cursor or blinking goes to the left edge of the display (in the first line if 2 lines are displayed). it also sets i/d to 1 (increment mode) in entry mode. s of entry mode does not change. return home return home sets ddram address 0 into the address counter, and returns the display to its original status if it was shifted. the ddram contents do not change. the cursor or blinking go to the left edge of the display (in the first line if 2 lines are displayed). entry mode set i/d: increments (i/d = 1) or decrements (i/d = 0) the ddram address by 1 when a character code is written into or read from ddram. the cursor or blinking moves to the right when incremented by 1 and to the left when decremented by 1. the same applies to writing and reading of cgram. s: shifts the entire display either to the right (i/d = 0) or to the left (i/d = 1) when s is 1. the display does not shift if s is 0. if s is 1, it will seem as if the cursor does not move but the display does. the display does not shift when reading from ddram. also, writing into or reading out from cgram does not shift the display. display on/off control d: the display is on when d is 1 and off when d is 0. when off, the display data remains in ddram, but can be displayed instantly by setting d to 1. c: the cursor is displayed when c is 1 and not displayed when c is 0. even if the cursor disappears, the function of i/d or other specifications will not change during display data write. the cursor is displayed using 5 dots in the 8th line for 5 8 dot character font selection and in the 11th line for the 5 10 dot character font selection (figure 13). b: the character indicated by the cursor blinks when b is 1 (figure 13). the blinking is displayed as switching between all blank dots and displayed characters at a speed of 409.6-ms intervals when f cp or f osc is 250 khz. the cursor and blinking can be set to display simultaneously. (the blinking frequency changes according to f osc or the reciprocal of f cp . for example, when f cp is 270 khz, 409.6 250/270 = 379.2 ms.)
hd44780u 27 cursor or display shift cursor or display shift shifts the cursor position or display to the right or left without writing or reading display data (table 7). this function is used to correct or search the display. in a 2-line display, the cursor moves to the second line when it passes the 40th digit of the first line. note that the first and second line displays will shift at the same time. when the displayed data is shifted repeatedly each line moves only horizontally. the second line display does not shift into the first line position. the address counter (ac) contents will not change if the only action performed is a display shift. function set dl: sets the interface data length. data is sent or received in 8-bit lengths (db7 to db0) when dl is 1, and in 4-bit lengths (db7 to db4) when dl is 0.when 4-bit length is selected, data must be sent or received twice. n: sets the number of display lines. f: sets the character font. note: perform the function at the head of the program before executing any instructions (except for the read busy flag and address instruction). from this point, the function set instruction cannot be executed unless the interface data length is changed. set cgram address set cgram address sets the cgram address binary aaaaaa into the address counter. data is then written to or read from the mpu for cgram.
hd44780u 28 code note: don? care. * code code code rs 0 r/w 0 db7 0 db6 0 db5 0 db4 0 db3 0 db2 0 db1 0 db0 1 rs 0 r/w 0 db7 0 db6 0 db5 0 db4 0 db3 0 db2 0 db1 1 db0 * rs 0 r/w 0 db7 0 db6 0 db5 0 db4 0 db3 0 db2 1 db1 i/d db0 s rs 0 r/w 0 db7 0 db6 0 db5 0 db4 0 db3 1 db2 d db1 c db0 b return home clear display entry mode set display on/off control rs 0 r/w 0 db7 0 db6 0 db5 0 db4 1 db3 s/c code db2 r/l db1 db0 code code higher order bit lower order bit * cursor or display shift function set set cgram address * rs 0 r/w 0 db7 0 db6 0 db5 1 db4 dl db3 n db2 f db1 db0 ** rs 0 r/w 0 db7 0 db6 1 db5 a db4 a db3 a db2 a db1 db0 aa note: don? care. * figure 11 instruction (1)
hd44780u 29 set ddram address set ddram address sets the ddram address binary aaaaaaa into the address counter. data is then written to or read from the mpu for ddram. however, when n is 0 (1-line display), aaaaaaa can be 00h to 4fh. when n is 1 (2-line display), aaaaaaa can be 00h to 27h for the first line, and 40h to 67h for the second line. read busy flag and address read busy flag and address reads the busy flag (bf) indicating that the system is now internally operating on a previously received instruction. if bf is 1, the internal operation is in progress. the next instruction will not be accepted until bf is reset to 0. check the bf status before the next write operation. at the same time, the value of the address counter in binary aaaaaaa is read out. this address counter is used by both cg and ddram addresses, and its value is determined by the previous instruction. the address contents are the same as for instructions set cgram address and set ddram address. table 7 shift function s/c r/l 0 0 shifts the cursor position to the left. (ac is decremented by one.) 0 1 shifts the cursor position to the right. (ac is incremented by one.) 1 0 shifts the entire display to the left. the cursor follows the display shift. 1 1 shifts the entire display to the right. the cursor follows the display shift. table 8 function set nf no. of display lines character font duty factor remarks 001 5 8 dots 1/8 011 5 10 dots 1/11 1*2 5 8 dots 1/16 cannot display two lines for 5 10 dot character font note: * indicates don? care.
hd44780u 30 cursor 5 8 dot character font 5 10 dot character font alternating display blink display example cursor display example figure 12 cursor and blinking rs 0 r/w 0 db7 1 db6 a db5 a db4 a db3 a code db2 a db1 a db0 a higher order bit lower order bit rs 0 r/w 1 db7 bf db6 a db5 a db4 a db3 a code db2 a db1 a db0 a higher order bit lower order bit set ddram address read busy flag and address figure 13 instruction (2)
hd44780u 31 write data to cg or ddram write data to cg or ddram writes 8-bit binary data dddddddd to cg or ddram. to write into cg or ddram is determined by the previous specification of the cgram or ddram address setting. after a write, the address is automatically incremented or decremented by 1 according to the entry mode. the entry mode also determines the display shift. read data from cg or ddram read data from cg or ddram reads 8-bit binary data dddddddd from cg or ddram. the previous designation determines whether cg or ddram is to be read. before entering this read instruction, either cgram or ddram address set instruction must be executed. if not executed, the first read data will be invalid. when serially executing read instructions, the next address data is normally read from the second read. the address set instructions need not be executed just before this read instruction when shifting the cursor by the cursor shift instruction (when reading out ddram). the operation of the cursor shift instruction is the same as the set ddram address instruction. after a read, the entry mode automatically increases or decreases the address by 1. however, display shift is not executed regardless of the entry mode. note: the address counter (ac) is automatically incremented or decremented by 1 after the write instructions to cgram or ddram are executed. the ram data selected by the ac cannot be read out at this time even if read instructions are executed. therefore, to correctly read data, execute either the address set instruction or cursor shift instruction (only with ddram), then just before reading the desired data, execute the read instruction from the second time the read instruction is sent. rs 1 r/w 1 db7 d db6 d db5 d db4 d db3 d code db2 d db1 d db0 d higher order bits lower order bits rs 1 r/w 0 db7 d db6 d db5 d db4 d db3 d code db2 d db1 d db0 d higher order bits lower order bits read data from cg or ddram write data to cg or ddram figure 14 instruction (3)
hd44780u 32 interfacing the hd44780u interface to mpus interfacing to an 8-bit mpu see figure 16 for an example of using a i/o port (for a single-chip microcomputer) as an interface device. in this example, p30 to p37 are connected to the data bus db0 to db7, and p75 to p77 are connected to e, r/ w , and rs, respectively. # )* 0 % & , + , rs r/w e internal operation db7 functioning data busy busy not busy data instruction write busy flag check busy flag check busy flag check instruction write figure 15 example of busy flag check timing sequence p30 to p37 p77 p76 p75 16 40 h8/325 hd44780u 8 db0 to db7 e rs r/w lcd com1 to com16 seg1 to seg40 figure 16 h8/325 interface (single-chip mode)
hd44780u 33 interfacing to a 4-bit mpu the hd44780u can be connected to the i/o port of a 4-bit mpu. if the i/o port has enough bits, 8-bit data can be transferred. otherwise, one data transfer must be made in two operations for 4-bit data. in this case, the timing sequence becomes somewhat complex. (see figure 17.) see figure 18 for an interface example to the hmcs4019r. note that two cycles are needed for the busy flag check as well as for the data transfer. the 4-bit operation is selected by the program. # $ * ' . / ! " ( ) rs r/w e internal operation db7 ir7 ir3 busy ac3 not busy ac3 d7 d3 instruction write busy flag check busy flag check instruction write note: ir7 , ir3 are the 7th and 3rd bits of the instruction. ac3 is the 3rd bit of the address counter. functioning
figure 17 example of 4-bit data transfer timing sequence d15 d14 d13 r10 to r13 rs r/w e db4 to db7 com1 to com16 seg1 to seg40 4 40 16 lcd hmcs4019r hd44780 figure 18 example of interface to hmcs4019r
hd44780u 34 interface to liquid crystal display character font and number of lines: the hd44780u can perform two types of displays, 5 8 dot and 5 10 dot character fonts, each with a cursor. up to two lines are displayed for 5 8 dots and one line for 5 10 dots. therefore, a total of three types of common signals are available (table 9). the number of lines and font types can be selected by the program. (see table 6, instructions.) connection to hd44780 and liquid crystal display: see figure 19 for the connection examples. table 9 common signals number of lines character font number of common signals duty factor 15 8 dots + cursor 8 1/8 15 10 dots + cursor 11 1/11 25 8 dots + cursor 16 1/16 com1 com8 seg1 seg40 com1 com11 seg1 seg40 hd44780 example of a 5 8 dot, 8-character 1-line display (1/4 bias, 1/8 duty cycle) example of a 5 10 dot, 8-character 1-line display (1/4 bias, 1/11 duty cycle) hd44780 figure 19 liquid crystal display and hd44780 connections
hd44780u 35 since five segment signal lines can display one digit, one hd44780u can display up to 8 digits for a 1-line display and 16 digits for a 2-line display. the examples in figure 19 have unused common signal pins, which always output non-selection waveforms. when the liquid crystal display panel has unused extra scanning lines, connect the extra scanning lines to these common signal pins to avoid any undesirable effects due to crosstalk during the floating state. com1 com8 seg1 seg40 hd44780 com9 com16 example of a 5 8 dot, 8-character 2-line display (1/5 bias, 1/16 duty cycle) figure 19 liquid crystal display and hd44780 connections (cont)
hd44780u 36 connection of changed matrix layout: in the preceding examples, the number of lines correspond to the scanning lines. however, the following display examples (figure 20) are made possible by altering the matrix layout of the liquid crystal display panel. in either case, the only change is the layout. the display characteristics and the number of liquid crystal display characters depend on the number of common signals or on duty factor. note that the display data ram (ddram) addresses for 4 characters 2 lines and for 16 characters 1 line are the same as in figure 19. com1 com8 seg1 seg40 com9 com16 hd44780 5 8 dot, 16-character 1-line display (1/5 bias, 1/16 duty cycle) figure 20 changed matrix layout displays
hd44780u 37 power supply for liquid crystal display drive various voltage levels must be applied to pins v1 to v5 of the hd44780u to obtain the liquid crystal display drive waveforms. the voltages must be changed according to the duty factor (table 10). vlcd is the peak value for the liquid crystal display drive waveforms, and resistance dividing provides voltages v1 to v5 (figure 21). table 10 duty factor and power supply for liquid crystal display drive duty factor 1/8, 1/11 1/16 bias power supply 1/4 1/5 v1 v cc ?/4 vlcd v cc ?/5 vlcd v2 v cc ?/2 vlcd v cc ?/5 vlcd v3 v cc ?/2 vlcd v cc ?/5 vlcd v4 v cc ?/4 vlcd v cc ?/5 vlcd v5 v cc ?lcd v cc ?lcd v cc v1 v4 v5 v2 v3 v cc v1 v2 v3 v4 v5 r r r r vr ? v v cc (+5 v) ? v v cc (+5 v) r r r r r vr vlcd vlcd 1/4 bias (1/8, 1/11 duty cycle) 1/5 bias (1/16, duty cycle) figure 21 drive voltage supply example
hd44780u 38 relationship between oscillation frequency and liquid crystal display frame frequency the liquid crystal display frame frequencies of figure 22 apply only when the oscillation frequency is 270 khz (one clock pulse of 3.7 m s). 1 2 3 4 8 1 2 1 2 3 4 11 1 2 1 2 3 4 16 1 2 400 clocks 400 clocks 200 clocks 1 frame 1 frame 1 frame 1/8 duty cycle 1/11 duty cycle 1/16 duty cycle v cc v1 v2 (v3) v4 v5 v cc v1 v2 (v3) v4 v5 v cc v1 v2 v3 v4 v5 com1 com1 com1 1 frame = 3.7 s 400 8 = 11850 s = 11.9 ms frame frequency = = 84.3 hz 1 11.9 ms 1 frame = 3.7 s 400 11 = 16300 s = 16.3 ms frame frequency = = 61.4 hz 1 16.3 ms 1 frame = 3.7 s 200 16 = 11850 s = 11.9 ms frame frequency = = 84.3 hz 1 11.9 ms figure 22 frame frequency
hd44780u 39 instruction and display correspondence 8-bit operation, 8-digit 1-line display with internal reset refer to table 11 for an example of an 8-digit 1-line display in 8-bit operation. the hd44780u functions must be set by the function set instruction prior to the display. since the display data ram can store data for 80 characters, as explained before, the ram can be used for displays such as for advertising when combined with the display shift operation. since the display shift operation changes only the display position with ddram contents unchanged, the first display data entered into ddram can be output when the return home operation is performed. 4-bit operation, 8-digit 1-line display with internal reset the program must set all functions prior to the 4-bit operation (table 12). when the power is turned on, 8-bit operation is automatically selected and the first write is performed as an 8-bit operation. since db0 to db3 are not connected, a rewrite is then required. however, since one operation is completed in two accesses for 4-bit operation, a rewrite is needed to set the functions (see table 12). thus, db4 to db7 of the function set instruction is written twice. 8-bit operation, 8-digit 2-line display for a 2-line display, the cursor automatically moves from the first to the second line after the 40th digit of the first line has been written. thus, if there are only 8 characters in the first line, the ddram address must be again set after the 8th character is completed. (see table 13.) note that the display shift operation is performed for the first and second lines. in the example of table 13, the display shift is performed when the cursor is on the second line. however, if the shift operation is performed when the cursor is on the first line, both the first and second lines move together. if the shift is repeated, the display of the second line will not move to the first line. the same display will only shift within its own line for the number of times the shift is repeated. note: when using the internal reset, the electrical characteristics in the power supply conditions using internal reset circuit table must be satisfied. if not, the hd44780u must be initialized by instructions. see the section, initializing by instruction.
hd44780u 40 table 11 8-bit operation, 8-digit 1-line display example with internal reset step instruction no. rs r/ w db7 db6 db5 db4 db3 db2 db1 db0 display operation 1 power supply on (the hd44780u is initialized by the internal reset circuit) initialized. no display. 2 function set 00001100* * sets to 8-bit operation and selects 1-line display and 5 8 dot character font. (number of display lines and character fonts cannot be changed after step #2.) 3 display on/off control 0000001110 _ turns on display and cursor. entire display is in space mode because of initialization. 4 entry mode set 0000000110 _ sets mode to increment the address by one and to shift the cursor to the right at the time of write to the dd/cgram. display is not shifted. 5 write data to cgram/ddram 1001001000 h_ writes h. ddram has already been selected by initialization when the power was turned on. the cursor is incremented by one and shifted to the right. 6 write data to cgram/ddram 1001001001 hi_ writes i. 7 8 write data to cgram/ddram 1001001001 hitachi_ writes i. 9 entry mode set 0000000111 hitachi_ sets mode to shift display at the time of write. 10 write data to cgram/ddram 1000100000 itachi _ writes a space.
hd44780u 41 table 11 8-bit operation, 8-digit 1-line display example with internal reset (cont) step instruction no. rs r/ w db7 db6 db5 db4 db3 db2 db1 db0 display operation 11 write data to cgram/ddram 1001001101 tachi m_ writes m. 12 13 write data to cgram/ddram 1001001111 microko_ writes o. 14 cursor or display shift 00000100* * microko _ shifts only the cursor position to the left. 15 cursor or display shift 00000100* * microko _ shifts only the cursor position to the left. 16 write data to cgram/ddram 1001000011 icroco _ writes c over k. the display moves to the left. 17 cursor or display shift 00000111* * microco _ shifts the display and cursor position to the right. 18 cursor or display shift 00000101* * microco_ shifts the display and cursor position to the right. 19 write data to cgram/ddram 1001001101 icrocom_ writes m. 20 21 return home 0000000010 hitachi _ returns both display and cursor to the original position (address 0).
hd44780u 42 table 12 4-bit operation, 8-digit 1-line display example with internal reset step instruction no. rs r/ w db7 db6 db5 db4 display operation 1 power supply on (the hd44780u is initialized by the internal reset circuit) initialized. no display. 2 function set 000010 sets to 4-bit operation. in this case, operation is handled as 8 bits by initializa- tion, and only this instruction completes with one write. 3 function set 000010 0000** sets 4-bit operation and selects 1-line display and 5 8 dot character font. 4-bit operation starts from this step and resetting is necessary. (number of display lines and character fonts cannot be changed after step #3.) 4 display on/off control 000000 001110 _ turns on display and cursor. entire display is in space mode because of initialization. 5 entry mode set 000000 000110 _ sets mode to increment the address by one and to shift the cursor to the right at the time of write to the dd/cgram. display is not shifted. 6 write data to cgram/ddram 100100 101000 h_ writes h. the cursor is incremented by one and shifts to the right. note: the control is the same as for 8-bit operation beyond step #6.
hd44780u 43 table 13 8-bit operation, 8-digit 2-line display example with internal reset step instruction no. rs r/ w db7 db6 db5 db4 db3 db2 db1 db0 display operation 1 power supply on (the hd44780u is initialized by the internal reset circuit) initialized. no display. 2 function set 00001110* * sets to 8-bit operation and selects 2-line display and 5 8 dot character font. 3 display on/off control 0000001110 _ turns on display and cursor. all display is in space mode because of initialization. 4 entry mode set 0000000110 _ sets mode to increment the address by one and to shift the cursor to the right at the time of write to the dd/cgram. display is not shifted. 5 write data to cgram/ddram 1001001000 h_ writes h. ddram has already been selected by initialization when the power was turned on. the cursor is incremented by one and shifted to the right. 6 7 write data to cgram/ddram 1001001001 hitachi_ writes i. 8 set ddram address 0011000000 hitachi _ sets ddram address so that the cursor is positioned at the head of the second line.
hd44780u 44 table 13 8-bit operation, 8-digit 2-line display example with internal reset (cont) step instruction no. rs r/ w db7 db6 db5 db4 db3 db2 db1 db0 display operation 9 write data to cgram/ddram 1001001101 hitachi m_ writes m. 10 11 write data to cgram/ddram 1001001111 hitachi microco_ writes o. 12 entry mode set 0000000111 hitachi microco_ sets mode to shift display at the time of write. 13 write data to cgram/ddram 1001001101 itachi icrocom_ writes m. display is shifted to the left. the first and second lines both shift at the same time. 14 15 return home 0000000010 hitachi microcom _ returns both display and cursor to the original position (address 0).
hd44780u 45 initializing by instruction if the power supply conditions for correctly operating the internal reset circuit are not met, initialization by instructions becomes necessary. refer to figures 23 and 24 for the procedures on 8-bit and 4-bit initializations, respectively. power on wait for more than 15 ms after v cc rises to 4.5 v wait for more than 4.1 ms wait for more than 100 s rs 0 r/w 0 db7 0 db6 0 db5 1 db4 1 db3db2 db1 db0 **** rs 0 r/w 0 db7 0 db6 0 db5 1 db4 1 db3 db2 db1 db0 **** rs 0 r/w 0 db7 0 db6 0 db5 1 db4 1 db3 db2 db1 *** db0 * rs 0 r/w 0 db7 0 db6 0 db5 1 db4 1 db3 n db2 f db1 db0 ** 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 i/d 0 1 s initialization ends bf cannot be checked before this instruction. function set (interface is 8 bits long.) bf cannot be checked before this instruction. function set (interface is 8 bits long.) bf cannot be checked before this instruction. function set (interface is 8 bits long.) bf can be checked after the following instructions. when bf is not checked, the waiting time between instructions is longer than the execution instuction time. (see table 6.) function set (interface is 8 bits long. specify the number of display lines and character font.) the number of display lines and character font cannot be changed after this point. display off display clear entry mode set wait for more than 40 ms after v cc rises to 2.7 v figure 23 8-bit interface
hd44780u 46 initialization ends wait for more than 15 ms after v cc rises to 4.5 v wait for more than 40 ms after v cc rises to 2.7 v bf cannot be checked before this instruction. function set (interface is 8 bits long.) bf cannot be checked before this instruction. function set (interface is 8 bits long.) bf cannot be checked before this instruction. function set (interface is 8 bits long.) db7 0 db6 0 db5 1 db4 1 rs 0 r/w 0 wait for more than 4.1 ms db7 0 db6 0 db5 1 db4 1 rs 0 r/w 0 wait for more than 100 s db7 0 db6 0 db5 1 db4 1 rs 0 r/w 0 db7 0 db6 0 db5 1 db4 0 rs 0 r/w 0 0 n 0 1 0 0 0 0 0 f 0 0 0 0 0 1 1 0 0 0 0 0 i/d 0 0 0 0 1 0 s 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ** bf can be checked after the following instructions. when bf is not checked, the waiting time between instructions is longer than the execution instuction time. (see table 6.) function set (set interface to be 4 bits long.) interface is 8 bits in length. display off display clear entry mode set function set (interface is 4 bits long. specify the number of display lines and character font.) the number of display lines and character font cannot be changed after this point. power on figure 24 4-bit interface
hd44780u 47 absolute maximum ratings* item symbol value unit notes power supply voltage (1) v cc ?nd ?.3 to +7.0 v 1 power supply voltage (2) v cc ?5 ?.3 to +13.0 v 1, 2 input voltage vt ?.3 to v cc +0.3 v 1 operating temperature t opr ?0 to +75 c storage temperature t stg ?5 to +125 c4 note: * if the lsi is used above these absolute maximum ratings, it may become permanently damaged. using the lsi within the following electrical characteristic limits is strongly recommended for normal operation. if these electrical characteristic conditions are also exceeded, the lsi will malfunction and cause poor reliability.
hd44780u 48 dc characteristics (v cc = 2.7 to 4.5 v, t a = ?0 to +75 c* 3 ) item symbol min typ max unit test condition notes* input high voltage (1) (except osc1) vih1 0.7v cc ? cc v6 input low voltage (1) (except osc1) vil1 ?.3 0.55 v 6 input high voltage (2) (osc1) vih2 0.7v cc ? cc v15 input low voltage (2) (osc1) vil2 0.2v cc v15 output high voltage (1) (db0?b7) voh1 0.75v cc v i oh = 0.1 ma 7 output low voltage (1) (db0?b7) vol1 0.2v cc vi ol = 0.1 ma 7 output high voltage (2) (except db0?b7) voh2 0.8v cc v i oh = 0.04 ma 8 output low voltage (2) (except db0?b7) vol2 0.2v cc vi ol = 0.04 ma 8 driver on resistance (com) r com 2 20 k w id = 0.05 ma, vlcd = 4 v 13 driver on resistance (seg) r seg 2 30 k w id = 0.05 ma, vlcd = 4 v 13 input leakage current i li ? 1 m a vin = 0 to v cc 9 pull-up mos current (db0?b7, rs, r/ w ) ? p 10 50 120 m av cc = 3 v power supply current i cc 150 300 m ar f oscillation, external clock v cc = 3 v, f osc = 270 khz 10, 14 lcd voltage vlcd1 3.0 11.0 v v cc ?5, 1/5 bias 16 vlcd2 3.0 11.0 v v cc ?5, 1/4 bias 16 note: * refer to the electrical characteristics notes section following these tables.
hd44780u 49 ac characteristics (v cc = 2.7 to 4.5 v, t a = ?0 to +75 c* 3 ) clock characteristics item symbol min typ max unit test condition note* external external clock frequency f cp 125 250 350 khz 11 clock external clock duty duty 45 50 55 % operation external clock rise time t rcp 0.2 m s external clock fall time t fcp 0.2 m s r f oscillation clock oscillation frequency f osc 190 270 350 khz r f = 75 k w , v cc = 3 v 12 note: * refer to the electrical characteristics notes section following these tables. bus timing characteristics write operation item symbol min typ max unit test condition enable cycle time t cyce 1000 ns figure 25 enable pulse width (high level) pw eh 450 enable rise/fall time t er , t ef 25 address set-up time (rs, r/ w to e) t as 60 address hold time t ah 20 data set-up time t dsw 195 data hold time t h 10 read operation item symbol min typ max unit test condition enable cycle time t cyce 1000 ns figure 26 enable pulse width (high level) pw eh 450 enable rise/fall time t er , t ef 25 address set-up time (rs, r/ w to e) t as 60 address hold time t ah 20 data delay time t ddr 360 data hold time t dhr 5
hd44780u 50 interface timing characteristics with external driver item symbol min typ max unit test condition clock pulse width high level t cwh 800 ns figure 27 low level t cwl 800 clock set-up time t csu 500 data set-up time t su 300 data hold time t dh 300 m delay time t dm ?000 1000 clock rise/fall time t ct 200 power supply conditions using internal reset circuit item symbol min typ max unit test condition power supply rise time t r cc 0.1 10 ms figure 28 power supply off time t off 1
hd44780u 51 dc characteristics (v cc = 4.5 to 5.5 v, t a = ?0 to +75 c* 3 ) item symbol min typ max unit test condition notes* input high voltage (1) (except osc1) vih1 2.2 v cc v6 input low voltage (1) (except osc1) vil1 ?.3 0.6 v 6 input high voltage (2) (osc1) vih2 v cc ?.0 v cc v15 input low voltage (2) (osc1) vil2 1.0 v 15 output high voltage (1) (db0?b7) voh1 2.4 v i oh = 0.205 ma 7 output low voltage (1) (db0?b7) vol1 0.4 v i ol = 1.2 ma 7 output high voltage (2) (except db0?b7) voh2 0.9 v cc v i oh = 0.04 ma 8 output low voltage (2) (except db0?b7) vol2 0.1 v cc vi ol = 0.04 ma 8 driver on resistance (com) rcom 2 20 k w id = 0.05 ma, vlcd = 4 v 13 driver on resistance (seg) rseg 2 30 k w id = 0.05 ma, vlcd = 4 v 13 input leakage current i li ? 1 m a vin = 0 to v cc 9 pull-up mos current (db0?b7, rs, r/ w ) ? p 50 125 250 m av cc = 5 v power supply current i cc 350 600 m ar f oscillation, external clock v cc = 5 v, f osc = 270 khz 10, 14 lcd voltage vlcd1 3.0 11.0 v v cc ?5, 1/5 bias 16 vlcd2 3.0 11.0 v v cc ?5, 1/4 bias 16 note: * refer to the electrical characteristics notes section following these tables.
hd44780u 52 ac characteristics (v cc = 4.5 to 5.5 v, t a = ?0 to +75 c* 3 ) clock characteristics item symbol min typ max unit test condition notes* external external clock frequency f cp 125 250 350 khz 11 clock external clock duty duty 45 50 55 % 11 operation external clock rise time t rcp 0.2 m s11 external clock fall time t fcp 0.2 m s11 r f oscillation clock oscillation frequency f osc 190 270 350 khz r f = 91 k w v cc = 5.0 v 12 note: * refer to the electrical characteristics notes section following these tables. bus timing characteristics write operation item symbol min typ max unit test condition enable cycle time t cyce 500 ns figure 25 enable pulse width (high level) pw eh 230 enable rise/fall time t er , t ef 20 address set-up time (rs, r/ w to e) t as 40 address hold time t ah 10 data set-up time t dsw 80 data hold time t h 10 read operation item symbol min typ max unit test condition enable cycle time t cyce 500 ns figure 26 enable pulse width (high level) pw eh 230 enable rise/fall time t er , t ef 20 address set-up time (rs, r/ w to e) t as 40 address hold time t ah 10 data delay time t ddr 160 data hold time t dhr 5
hd44780u 53 interface timing characteristics with external driver item symbol min typ max unit test condition clock pulse width high level t cwh 800 ns figure 27 low level t cwl 800 clock set-up time t csu 500 data set-up time t su 300 data hold time t dh 300 m delay time t dm ?000 1000 clock rise/fall time t ct 100 power supply conditions using internal reset circuit item symbol min typ max unit test condition power supply rise time t rcc 0.1 10 ms figure 28 power supply off time t off 1
hd44780u 54 electrical characteristics notes 1. all voltage values are referred to gnd = 0 v. v cc a b a 1.5 v b 0.25 a 3 the conditions of v1 and v5 voltages are for proper operation of the lsi and not for the lcd output level. the lcd drive voltage condition for the lcd output level is specified as lcd voltage vlcd. a = b = v cc ?5 v cc ?1 v1 v5 2. v cc 3 v1 3 v2 3 v3 3 v4 3 v5 must be maintained. 3. for die products, specified at 75 c. 4. for die products, specified by the die shipment specification. 5. the following four circuits are i/o pin configurations except for liquid crystal display output. pmos nmos v cc v cc pmos nmos (pull up mos) pmos v cc pmos nmos v cc nmos nmos v cc pmos nmos (output circuit) (tristate) output enable data (pull-up mos) i/o pin pins: db0 ?b7 (mos with pull-up) input pin pin: e (mos without pull-up) pins: rs, r/w (mos with pull-up) output pin pins: cl1, cl2, m, d v cc (input circuit) pmos pmos input enable
hd44780u 55 6. applies to input pins and i/o pins, excluding the osc1 pin. 7. applies to i/o pins. 8. applies to output pins. 9. current flowing through pull?p moss, excluding output drive moss. 10. input/output current is excluded. when input is at an intermediate level with cmos, the excessive current flows through the input circuit to the power supply. to avoid this from happening, the input level must be fixed high or low. 11. applies only to external clock operation. oscillator osc1 osc2 0.7 v cc 0.5 v cc 0.3 v cc th tl t rcp t fcp duty = 100% th th + tl open 12. applies only to the internal oscillator operation using oscillation resistor r f . osc1 osc2 r f r : r : f f 75 k 2% (when v cc = 3 v) 91 k 2% (when v cc = 5 v) w 500 400 300 200 100 50 100 150 (91) r (k ) f w f (khz) osc v cc = 5 v 500 400 300 200 100 50 100 150 r (k ) f w f (khz) osc v cc = 3 v typ. since the oscillation frequency varies depending on the osc1 and osc2 pin capacitance, the wiring length to these pins should be minimized. (270) (270) w (75) typ. max. min. max. min.
hd44780u 56 13. rcom is the resistance between the power supply pins (v cc , v1, v4, v5) and each common signal pin (com1 to com16). rseg is the resistance between the power supply pins (v cc , v2, v3, v5) and each segment signal pin (seg1 to seg40). 14. the following graphs show the relationship between operation frequency and current consumption. 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 0 100 200 300 400 500 v cc = 5 v 0 100 200 300 400 500 v cc = 3 v f osc or f cp (khz) f osc or f cp (khz) i cc (ma) i cc (ma) max. typ. max. typ. 15. applies to the osc1 pin. 16. each com and seg output voltage is within 0.15 v of the lcd voltage (v cc , v1, v2, v3, v4, v5) when there is no load.
hd44780u 57 load circuits data bus db0 to db7 for v = 4.5 to 5.5 v cc test point 90 pf 11 k w v = 5 v cc 3.9 k w is2074 diodes h for v = 2.7 to 4.5 v cc test point 50 pf external driver control signals: cl1, cl2, d, m test point 30 pf
hd44780u 58 timing characteristics rs r/w e db0 to db7 vih1 vil1 vih1 vil1 t as t ah vil1 vil1 t ah pw eh t ef vih1 vil1 vih1 vil1 t er t dsw t h vih1 vil1 vih1 vil1 t cyce vil1 valid data figure 25 write operation rs r/w e db0 to db7 vih1 vil1 vih1 vil1 t as t ah vih1 vih1 t ah pw eh t ef vih1 vil1 vih1 vil1 t ddr t dhr t er vil1 voh1 vol1 * voh1 * vol1 valid data t cyce note: * vol1 is assumed to be 0.8 v at 2 mhz operation. figure 26 read operation
hd44780u 59 cl1 cl2 d m voh2 voh2 vol2 t ct t cwh t cwh t csu voh2 t csu t cwl t ct t dh t su voh2 t dm voh2 vol2 vol2 figure 27 interface timing with external driver v cc 0.2 v 2.7 v/4.5 v* 2 0.2 v 0.2 v t rcc t off *1 0.1 ms t rcc 10 ms t off 1 ms 3 notes: 1. 2. 3. t off compensates for the power oscillation period caused by momentary power supply oscillations. specified at 4.5 v for 5-v operation, and at 2.7 v for 3-v operation. for if 4.5 v is not reached during 5-v operation, the internal reset circuit will not operate normally. in this case, the lsi must be initialized by software. (refer to the initializing by instruction section.) figure 28 internal power supply reset

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