NEC PD17062 - Manual (Page 245)

245
µ
PD17062
b
3
b
2
b
1
b
0
0 0 IDCEN
0
1
0
Turns off the display.
Turns on the display.
(RF 31H)
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20.3 IDC ENABLE FLAG
The IDCEN (IDC enable) flag is manipulated to start IDC operations (turn on the display). The flag is mapped
at the lowest bit (#0) of the register file at 31H.
Table 20-2 IDCEN Flag
(1) Cautions in turning on the display
(a) The IDCEN flag must be set to 1 (begin displaying), when the vertical sync signal (Vsync) is high
(vertical flyback time: Vsync = low level) after the IDCDMAEN flag (RF, at 00H, #1) is turned on.
(b) Do not write data to VRAM, when the IDCEN flag is 1 (display turned on).
Sample program
SET1 IDCDMAEN ; Sets the DMA mode.
CLR1 IDCEN ; If the display is on when VRAM data is to be specified,
; reset the IDCEN (turn off the display).
Sets data in VRAM. ; Sets VRAM data.
LOOP
SKF1 INTVSYN ; Makes sure Vsync = low level, and sets the IDCEN.
BR LOOP
SET1 IDCEN ; Turns on the display.
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