Panning Offset Register (Posr); Gray-Scale Control Registers; Frame-Rate Modulation Control Register (Frcm); Gray Palette Mapping Register (Gpmr) - Motorola DragonBall MC68328 User Manual

4.7.5.5 PANNING OFFSET REGISTER (POSR).

BOS Byte Offset
BOS is used primarily in the non-gray scale mode and in conjunction with POS0-2. (BOS
must be set to zero for gray-scale data).
0 = Start from the first byte when retrieving binary pixel data for display
1 = Active display will start from the second byte instead
The cursor reference position must be adjusted separately with
software when this register is changed.
POS2-POS0
POS specifies which of the 8 pixels in the first or second (GS=0, BOS=1 only) octet re-
trieved from the line buffer is the first to be displayed on the screen. (e.g. 000 implies that
pixel 7, the first shifted out, will be the first to be displayed on every horizontal line in the
current frame).

4.7.6 Gray-Scale Control Registers

4.7.6.1 FRAME-RATE MODULATION CONTROL REGISTER (FRCM) .

Figure 4-24. Frame-Rate Modulation Control Register
XMOD, YMOD
These numbers modulate adjacent pixels at different time periods to avoid spatial flicker
or jitter when using FRC. These values must be optimized by manually fine tuning the tar-
get LCD panel. See Section 4.5.5 Gray Palette Mapping for details.

4.7.6.2 GRAY PALETTE MAPPING REGISTER (GPMR).

15 14 13 12
0 G12 G11 G10
Address: $(FF)FFFA32
GMN
Gray palette code (bit position n=0, 1, 2) output for pixel-input data m (0 for pixel data 00,
1=01, 2=10, 3=11). This 3-bit code will then select one of 7 bitstreams of different densi-
ties. See Section 4.5.5 Gray Palette Mapping for details.
MOTOROLA MC68328 DRAGONBALL PROCESSOR USER'S MANUAL
7 6 5
UNUSED
Address: $(FF)FFFA2D
Figure 4-23. Panning Offset Register
Pixel Offset Code
7 6 5
XMOD3-XMOD0
Address: $(FF)FFFA31
Frame-Rate Modulation Control
11 10 9
0 G02 G01
Figure 4-25. Gray Palette Mapping Register
4 3 2 1
BOS POS2 POS1
Reset Value: $00
NOTE
4 3 2 1
YMOD3-YMOD0
Reset Value: $B9
8 7 6 5
G00 0 G32 G31
LCD Controller
0
POS0
0
4 3 2 1
G30 0 G22 G21
Reset Value: $0173
0
G20
4-19