HD44780U Datasheet, PDF (8/59 Pages) Hitachi Semiconductor – Dot Matrix Liquid Crystal Display Controller/Driver

HD44780U
Pin Functions
Signal
RS
No. of
Lines I/O
1
I
R/W
1
I
E
1
I
DB4 to DB7
4
I/O
DB0 to DB3
4
I/O
CL1
1
O
CL2
1
O
M
1
O
D
1
O
COM1 to COM16 16
O
SEG1 to SEG40 40
O
V1 to V5
5
—
V_CC, GND
2
—
OSC1, OSC2 2
—
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:
address counter (for read)
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_CC –V5 = 11 V (max)
V_CC: 2.7V to 5.5V, GND: 0V
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.
8