HD44780U Hitachi Semiconductor (acquired by Renesas), HD44780U Datasheet - Page 26

• Manufacturer Part Number: HD44780U
• Description: Dot Matrix Liquid Crystal Display Controller/driver
• Manufacturer: Hitachi Semiconductor (acquired by Renesas)

HD44780U
Table 6
Instruction RS
Write data
to CG or
DDRAM
Read data
from CG or
DDRAM
Note:
192
— indicates no effect.
*
1
1
I/D
I/D
S
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
N
F
BF
BF
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
counter is updated.
Instructions (cont)
= 1: Increment
= 0: Decrement
= 1: Accompanies display shift
= 1: 8 bits, DL = 0: 4 bits
= 1: 2 lines, N = 0: 1 line
= 1: 5
= 1: Internally operating
= 0: Instructions acceptable
R/
0
1
: :
DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 Description
Write data
Read data
Busy signal
(DB7 pin)
Address counter
(DB0 to DB6 pins)
Note: t
10 dots, F = 0: 5
t
ADD
ADD
depends on the operation frequency
= 1.5/(f
Code
Figure 10 Address Counter Update
ADD
cp
is the time elapsed after the busy flag turns off until the address
or f
OSC
8 dots
Busy state
) seconds
A
t
ADD
Writes data into DDRAM or
CGRAM.
Reads data from DDRAM or
CGRAM.
DDRAM: Display data RAM
CGRAM: Character generator
ACG:
ADD:
AC: Address counter used for
(corresponds to cursor
address)
both DD and CGRAM
addresses
RAM
CGRAM address
DDRAM address
A + 1
Execution Time
(max) (when f
37 µs
t
37 µs
t
Execution time
changes when
frequency changes
Example:
When f
250 kHz,
37 s
f
ADD
ADD
OSC
= 4 µs*
= 4 µs*
is 270 kHz)
270
250
cp
= 40
or f
OSC
s
cp
is
or