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jlackey
213 Posts |
 Posted - 20 Dec 2002 : 15:59:30
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LCD Panel Configuration
Note that this topic only applies when using the ADS bootloader. When using the U-Boot bootloader see the "Hardware configuration files" section of U-Boot bootloader Configuration Files.
Most Eurotech Linux kernels are configured to support the Sharp LQ64D343 and Gold Star LP064v1 VGA flat panels. Other panels can be used by setting the video frame buffer registers to appropriate values.
Using at least Ver 4.3 of the Eurotech Linux Bootloader and either Linux 2.4.19-rmk6-ads3 on SA11x0 based boards or 2.4.19-rmk7-pxa1-adsx2 for boards with an XScale CPU, the video frame buffer registers can be configured using a register.txt file. During the boot process the bootloader reads this file and sets the registers. The kernel uses and maintains the values set by the bootloader. When you use the bootloader to program the On-Board Flash, the register settings in the register.txt file are stored with the kernel zImage.
Each line in the file specifies a register (address) and a value to set. For example:
0xb0100010 0xffff2000 ; DBAR1 - 16 bpp Values must be in hexadecimal and may be 8, 16, or 32 bits. The size is determined by number of digits.
The registers that need to be configured depend on which frame buffer you are using. Currently, there is an optional Epson graphics accellerator on the Advanced Graphics Client. Boards with this option use the Epson frame buffer. All other boards (and the AGC without the Epson chip) use either the SA11x0 frame buffer or the PXA (XScale) frame buffer.
Here are files for panels connected to the SA11x0 frame buffer:
Here are files for panels connected to the PXA frame buffer:
Here are files for the Advanced Graphics Client with an Epson graphics chip:
And here is a file for the AGX with an Epson graphics chip:
Rename the file to register.txt or copy the contents to your existing register.txt file to chage your panel configuration. As they become available, additional register files will be provided here.
Moving from an SA11x0 based board to one that uses a PXA CPU
If you are transitioning from one of our products that uses an SA11x0 CPU to one that uses a PXA CPU and you use a register.txt file, then you need to get a new register.txt file to use with your new board. The registers that control the frame buffer on the SA11x0 and the PXA have different addresses and different fields. Do not use a register.txt file intended for one CPU on a board that uses another CPU.
Windows CE Hardware Tables
You can use the LCD register settings found in adsload.hwt files provided for Windows CE boards on your Linux board, too. Download one of the CPU frame buffer files provided above and replace the register settings LCCR0 through LCCR3 with the ones from the adsload.hwt that corresponds to your display. Note that for Linux on an SA11x0 based board, you must also set the DBAR1 register to configure the bits per pixel (0xffff1000 for 8 bpp, 0xffff2000 for 16 bpp).
Changing the Panel Settings the old way
With older kernels and bootloaders, the frame buffer driver must be modified to support different panels. The register files above may be used as a guide for what changes are needed. For the SA11x0 frame buffer, update the drivers/video/sa1100fb.c file. For the Epson frame buffer, update the drivers/video/epson13806fb.c file.
More information
For further reading about displays on Eurotech products, see the display topic index.
29-Jan-2004: jlackey - add AGX Epson graphics chip file
15-Sep-2003: jlackey - add warning on how CPU registers differ
28-May-2003: jlackey - add PXA frame buffer files
04-Mar-2003: jlackey - change bootloader to Ver 4.3 (improves bits per pixel configuration on the sa1100 frame buffer); update sa1100 register files
21-Feb-2003: jlackey - change bootloader to Ver 4.2 since this version is required to configure the Epson frame buffer registers
13-Jan-2003: akidder - add link to display topic index
13-Jan-2003: jlackey - add instructions for using register settings from Windows CE |
Edited by - adrian on 10 Jan 2008 13:34:28 |
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