Rainbow Electronics HD44780 - Manual (Page 45)

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 µ 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