
1997 Dec 16
37
Philips Semiconductors
Product specification
LCD controller/driver
PCF2104x
Table 6
4-bit operation, 1-line display example; using internal reset
STEP
INSTRUCTION
DISPLAY
OPERATION
1
Power supply on (PCF2104x is
initialized by the internal reset circuit).
Function set:
RS = 0; R/W = 0; DB7 = 0; DB6 = 0;
DB5 = 1; DB4 = 0
Initialized. No display appears.
2
Sets to 4-bit operation. In this instance operation is
handled as 8-bits by initialization and only this
instruction completes with one write.
3
Function set:
RS = 0; R/W = 0; DB7 = 0; DB6 = 0;
DB5 = 1; DB4 = 0
RS = 0; R/W = 0; DB7 = 0; DB6 = 0;
DB5 = 0; DB4 = 0
Display on/off control:
RS = 0; R/W = 0; DB7 = 0; DB6 = 0;
DB5 = 0; DB4 = 0
RS = 0; R/W = 0; DB7 = 1; DB6 = 1;
DB5 = 1; DB4 = 0
Entry mode set:
RS = 0; R/W = 0; DB7 = 0; DB6 = 0;
DB5 = 0; DB4 = 0
RS = 0; R/W = 0; DB7 = 0; DB6 = 1;
DB5 = 1; DB4 = 0
Write data to CGRAM/DDRAM:
RS = 1; R/W = 0; DB7 = 0; DB6 = 1;
DB5 = 0; DB4 = 1
RS = 1; R/W = 0; DB7 = 0; DB6 = 1;
DB5 = 1; DB4 = 0
Sets to 4-bit operation, selects 2
×
12 display.
4-bit operation starts from this point and resetting is
needed.
4
Turns on display and cursor.
Entire display is blank after initialization.
5
_
Sets mode to increment the address by 1 and to shift the
cursor to the right at the time of write to the DD/CGRAM.
Display is not shifted.
6
P_
Writes ‘P’. The DDRAM has already been selected by
initialization at power-on.
The cursor is incremented by 1 and shifted to the right.