HD44780 Hitachi Semiconductor (acquired by Renesas), HD44780 Datasheet - Page 8

• Manufacturer Part Number: HD44780
• Description: Dot Matrix Liquid Crystal Display Controller/driver
• Manufacturer: Hitachi Semiconductor (acquired by Renesas)

HD44780U
Pin Functions
Signal
RS
R/W
E
DB4 to DB7
DB0 to DB3
CL1
CL2
M
D
COM1 to COM16 16
SEG1 to SEG40 40
V1 to V5
V
OSC1, OSC2
8
CC
, GND
No. of
Lines
1
1
1
4
4
1
1
1
1
5
2
2
I/O
I
I
I
I/O
I/O
O
O
O
O
O
O
—
—
—
Device
Interfaced with
MPU
MPU
MPU
MPU
MPU
Extension driver
Extension driver
Extension driver
Extension driver
LCD
LCD
Power supply
Power supply
Oscillation
resistor clock
Function
Selects registers.
0: Instruction register (for write) Busy flag:
1: Data register (for write and read)
Selects read or write.
0: Write
1: Read
Starts data read/write.
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.
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.
Clock to latch serial data D sent to the extension
driver
Clock to shift serial data D
Switch signal for converting the liquid crystal
drive waveform to AC
Character pattern data corresponding to each
segment signal
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.
Segment signals
Power supply for LCD drive
V
V
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.
CC
CC
address counter (for read)
: 2.7V to 5.5V, GND: 0V
–V5 = 11 V (max)