NEC Advanced Personal Computer System Reference Manual page 82

Controller PCB
Table 3-5 GDC Commands (cont'd)
COMMAND/
DATA BUS
PARAMETER 07 06 05 04 03 02
DI DO REMARKS
HIGH BYTE CODER Reads the high-
C I
a
I I
I
o
~MOD~ order byte of the
character-code data
from the display
memory.
CSR R Reads the display
C I I I
a a a a a
position of the cursor.
WORD DREQW Requests a DMA
C
a a
I
a a
I ~MOD
. .
write transfer for the
entire word.
LOW BYTE DREQW Requests a DMA
C
a a
I I
a
I ~MOD~ write transfer for the
low-order byte only.
HIGH BYTE DREQW Requests a DMA
C
a a
I I I I ~MOD'" write transfer for the
high-order byte only.
WORD DREQR Requests a DMA
C I
a
I
a a
I .... MOD ...
read transfer for the
entire word.
LOW BYTE DREQR Requests a DMA
C I 0 I I
a
I ~MOD'" read transfer for the
low-order byte only.
HIGH BYTE DREQR Requests a DMA
C I 0 I I I
I .... MOD ...
read transfer for the
high-order byte only.
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