SED1354 Datasheet, PDF (173/472 Pages) Epson Company – Color Graphics LCD/CRT Controller

Epson Research and Development
Vancouver Design Center
Page 33
6 CRT Considerations
6.1 Introduction
The CRT timing is based on both the “VESA Monitor Timing Standards Version 1.0” and “Frame
Rate Calculation (Chapter 11)” in SED1354 Hardware Functional Specification. The following
sections describe CRT considerations.
6.1.1 CRT Only
For CRT only, the Dual/Single Panel Select bit of Panel Type Register (REG[02h]) must first be set
to single passive LCD panel. The monitor configuration registers then need to be set to follow the
VESA timing standard.
Note
If only the CRT is used, it is also useful to disable the LCD power (set REG[1Ah] bit 4 = 1). This
will reduce power consumption.
To program the external RAMDAC, set the CRT Enable bit in the Display Mode Register
(REG[0Dh]) to 1. Once the CRT is enabled, the GPIO registers will be automatically set to access
the external RAMDAC. Next, program the RAMDAC Write Mode Address register and the
RAMDAC Palette Data register as desired (refer to sample code in 9.1.2 for details).
When programming the RAMDAC control registers, connect the RAMDAC to the low-byte of the
CPU data bus for Little-Endian architecture and the high-byte for Big-Endian architecture. The
RAMDAC registers are mapped as follows:
Table 6-1: RAMDAC Register Mapping for Little/Big-Endian
Register Name
RAMDAC Pixel Read Mask
RAMDAC Read Mode Address
RAMDAC Write Mode Address
RAMDAC Palette Data
Little-Endian
REG[28h]
REG[2Ah]
REG[2Ch]
REG[2Eh]
Big-Endian
REG[29h]
REG[2Bh]
REG[2Dh]
Reg[2Fh]
Note
When accessing the External RAMDAC Control registers with either of the Little-Endian or
Big-Endian architectures described above, accessing the adjacent unused registers is prohibited.
Table 6-2 shows some example register data for setting up CRT only mode for certain combinations
of resolutions, frame rates and pixel clocks. All the examples in this chapter are assumed to be for a
Little-Endian system, 8 bpp color depth and 2M bytes of 60ns EDO-DRAM.
Programming Notes and Examples
Issue Date: 98/10/28
SED1354
X19A-G-002-06