Lmmc (Logical Move Cpu To Vram) - Yamaha V9938 Programmer's Manual

4.4.5. LMMC (Logical move CPU to VRAM)

LMMC command is used to transfer data from the CPU to video or expansion RAM
into a specified rectangular area through VDP. The units used are dots.
CPU
LMMC execution order
Step 1: Set necessary coordinates in command registers
MSB
R#36
R#37
R#38
R#39
R#40
R#41
R#42
R#43
Step 2: Set color register value
The first byte transferred from CPU after starting executing the LMMC command
should be located in color register R#44 (CLR). Format of color data depends on the
graphics mode.
MSB
R#44
© 1985 ASCII CORP. / NIPPON GAKKI CO.
VDP
7 6 5
DX7 DX6 DX5
0 0 0
DY7 DY6 DY5
0 0 0
NX7 NX6 NX5
0 0 0
NY7 NY6 NY5
0 0 0
7 6 5
- - -
- - -
CR7 CR6 CR5
Video or expansion RAM
(DX, DY)
NY
↓
4 3 2
DX4 DX3 DX2
0 0 0
DY4 DY3 DY2
0 0 0
NX4 NX3 NX2
0 0 0
NY4 NY3 NY2
0 0 0
4 3 2
- CR3 CR2
- - -
CR4 CR3 CR2
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NX
DIY
1 0 LSB
DX1 DX0 DX: Destination
X (0...511)
0 DX8
DY1 DY0 DY: Destination
Y (0...1023)
DY9 DY8
NX1 NX0 NX: Number of
dots in X-axis
0 NX8
NY1 NY0 NY: Number of
NY9 NY8 dots in Y-axis
1 0 LSB
CR1 CR0 G4, G6
CR1 CR0 G5
CR1 CR0 G7
© 2010-2015 Eugeny Brychkov
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