MZ3500
(Subroutine lo send command and parameter to the GDC
via the FIFO)
HL reg — First address of the command code oarameter table.
B. reg — Q'ty of data.
C reg ^ 60H (graphic GDC), 70H (character GDC)
N
> FIFO Empty?
OUTl
; COMMAND — GDC
RET
Example of graphic drawing by GDC
1) Dot display
VRAM 16-bit
structure
Example to display a dot on the fourth bit of the address
CSRW C
49H
- COMMAND CODE
PI 01H
— Low order one byte of the
ab
solute address
P2
ООН — High order one byte
of
The
ab
solute address
P3
ЗОН
— Dot address (dAD)
WRITE C 23H - COMMAND CODE
VECTE
C 6CH - COMMAND CODE
49 -
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