Idc Enable Flag - NEC PD17062 Datasheet

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.
(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
CLR1
Sets data in VRAM.
LOOP
SKF1
BR
SET1
Table 20-2 IDCEN Flag
b b b b
3 2 1 0
0 0 0 IDCEN
IDCDMAEN ; Sets the DMA mode.
IDCEN ; If the display is on when VRAM data is to be specified,
; reset the IDCEN (turn off the display).
; Sets VRAM data.
INTVSYN ; Makes sure Vsync = low level, and sets the IDCEN.
LOOP
IDCEN ; Turns on the display.
(RF 31H)
0 Turns off the display.
1 Turns on the display.
PD17062
245