Hitachi HD44780 - Internal Reset Procedure; Display Clear; Function Set; Display On;Off Control

2
4-bit interface
z bus lines DB0-DB3 disabled
z 4 high order bits followed by 4 low order bits
Display addressing
Display position 1 2 3 4 5 … 39 40
DDRAM address
(row 1)
00 01 02 03 04 … 26 27
DDRAM address
(row 2)
40 41 42 43 44 … 66 67
Instruction Set
1. Designate functions
(display format, data length etc.)
2. Set internal RAM address
Dt t f
3.
D
a
t
a
t
rans
f
e
r
4. Miscellaneous functions
s
6
instuctions
1 tclock tick @ 16MHz = 62.5 n
s
1us = 1000us/(62.5ns/instr) = 1
6
37us = 592 instructions
Instructions - Legend Internal Reset Procedure
1. Display clear
2. Function set:
DL = 1; 8-bit interface data
N = 0; 1-line display
F = 0; 5 x 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