LH79524/LH79525 User’s Guide
Color Liquid Crystal Display Controller
Version 1.0
4-29
4.5.3.7 CLCDC Control Register (CTRL)
CTRL controls the CLCDC operating mode. All registers should be set up prior to program-
ming LCDEN to 1.
Note that the operating mode (color/mono, bits-per-pixel, etc.) can only be changed
between frames to avoid corruption of the current frame data. To ensure this is done prop-
erly, use the Vertical Compare Interrupt to detect that the current frame is complete. To do
this, follow these steps when changing operating mode:
1.
Program the CTRL: VCI bit to 0b00 to generate the Vertical Compare Interrupt on entry
to the Sync State. Enable this interrupt by programming the INTREN:VCIEN bit to 1.
2.
Program the CTRL:LCDEN bit to 0. The controller will complete the current frame
before sampling this bit.
3.
Wait for the Vertical Compare Interrupt. Upon assertion of the interrupt, program the
new mode (e.g. from color to monochrome using the CTRL:BW bit).
Then program the CTRL:LCDEN bit to 1 and clear the Vertical Compare Interrupt by writ-
ing a 1 to the STATUS:VCI bit. The CLCDC will resume operating, using the newly pro-
grammed parameters.
Table 4-26. CTRL Register
BIT
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
FIELD
///
WAT
E
RMARK
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RW
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RW
BIT
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FIELD
///
VCI
PWR
BEPO
BEBO
BG
R
DUAL
MONO
8
L
TF
T
BW
BPP
L
CDEN
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RW
RW
RW
RW
RW
RW
RO
RO
RW
RW
RW
RW
RW
RW
RW
RW
RW
ADDR
0xFF 0x1C