pcf2119x-2 NXP Semiconductors, pcf2119x-2 Datasheet - Page 24

• Manufacturer Part Number: pcf2119x-2
• Description: Controllers/drivers
• Manufacturer: NXP Semiconductors

Philips Semiconductors
8.1
‘Clear display’ writes character code 20H into all DDRAM
addresses (the character pattern for character code 20H
must be a blank pattern), sets the DDRAM address
counter to logic 0 and returns the display to its original
position, if it was shifted. Thus, the display disappears and
the cursor or blink position goes to the left edge of the
display. Sets entry mode I/D = 1 (increment mode). S of
entry mode does not change.
The instruction ‘clear display’ requires extra execution
time. This may be allowed by checking the Busy Flag (BF)
or by waiting until the 165 clock cycles have elapsed.
The latter must be applied where no read-back options are
foreseen, as in some Chip-On-Glass (COG) applications.
8.2
‘Return home’ sets the DDRAM address counter to logic 0
and returns the display to its original position if it was
shifted. DDRAM contents do not change. The cursor or
blink position goes to the left of the first display line.
I/D and S of entry mode do not change.
28. August 2000
LCD controllers/drivers
Clear display
Return home
internal
R/W
DB7
RS
E
instruction
write
data
Fig.16 Example of busy flag checking timing sequence.
busy flag
internal operation
busy
check
24
busy flag
check
busy
8.3
8.3.1
When I/D = 1 (0) the DDRAM or CGRAM address
increments (decrements) by 1 when data is written into or
read from the DDRAM or CGRAM. The cursor or blink
position moves to the right when incremented and to the
left when decremented. The cursor underline and cursor
character blink are inhibited when the CGRAM is
accessed.
8.3.2
When S = 1, the entire display shifts either to the right
(I/D = 0) or to the left (I/D = 1) during a DDRAM write. Thus
it appears as if the cursor stands still and the display
moves. The display does not shift when reading from the
DDRAM, or when writing to or reading from the CGRAM.
When S = 0, the display does not shift.
Entry mode set
I/D
S
busy flag
check
busy
not
instruction
data
write
PCF2119x-2
Product specification
MGA806