Atlas and Elpin VGA-Bios initialization problem

[babak2]

Posted on July 08, 2003 at 15:30

Atlas and Elpin VGA-Bios initialization problem

[babak2]

Posted on July 07, 2003 at 12:44

Vi are using Elpin Systems VGA-Bios V2.59c, include 640x480 TFT support, in a new design based on STPC-Atlas.

In most cases everything functions OK! Except that sometimes during system boot-up and Video initialization by VGA-Bios, the LCD becomes totally green or red and it beeps 1-long and 3-short beeps! and then it goes on as usual without any problems and it seems that everything such as memory & VGA and graphics functioning properly. (The application initializes it in VESA mode 101 without any problem!)

The other case that happens is, that sometimes after VGA initialization

(without any error indication or above beeps, there is no color on the

LCD! Neither in mode 3 nor mode 12, which should have 16-colors! The controller is in some gray mode!!

The application is still able to put it in VESA graphic mode 101 with full color and without any problem!

Does anyone know which error is indicated by 1-long and 3-short beeps? Is it memory or adapter error?

We are using General Software EBIOS 2000.

Any suggestions?

Best Regards, /Babakm

[thierry239955_st]

Posted on July 08, 2003 at 07:02

Hello Babakm,

Quite a strange behaviour! Do you have an evaluation board from ST to test with the same BIOS? It would be interesting to understand if it is a software/BIOS related problem or if it is due to your specific design.

For the second problem (gray mode), it is not important if you can't connect your TFT on eval board. The pixels sent to the TFT are the same as VGA output and it is not possible the TFT interface convert them into gray scale. You should have the same behaviour on VGA. In fact, its look like the VGA BIOS doesn't detect a graphic chipset and think it is a monochrome card (or choose monochrome by default). The new VESA modes like the 101 are always color but old VGA mode can be either color or monochrome. New graphics chipset are still able to emulate old graphic card for backward compatibility reason.

For your first problem, did you notice if after the beeps, the system reset and reboot from scratch. It would be more understandable if your system fail one boot with this strange behaviour then restart in the right way.

Farfalla

[babak2]

Posted on July 08, 2003 at 15:30

Hi Farfalla!

Thanks a lot for your response!

No, we haven’t any ST evaluation board to test. Video controller and the VGA-Bios of course generates what we see on the LCD screen.

Both errors seem to depend on VGA controller (It could be the memory access) or VGA bios.

We cannot find any memory error or memory access error on the board. (Neither with the bios memory test nor any other memory test utility.)

* Different clock speed, both HCLK & MCLK in both synchronous and asynchronous mode has been tested without any success!

* For your information I must say that if we cool down the controller it seems that the errors disappear until the ATLAS became warmer!

* In SDRAM REGISTER 0 the ReadClock feature for CRTC has been enabled, but disabled for GE & Host. The delay is 0.

Both errors appears when you boot the system.

About your question that if after error beeps (1-L, 3-S) the system fails?

No, it does not. It could happen every time you reboot the system. Everything seems to be OK! Our splash screen shows right colors and the system starts correctly! I cannot understand which error the VGA-Bios indicates by beeping? And why?

And the other case (gray mode), VGA Bios detects something! WITHOUT ANY ERROR!

Our splash screen shows the correct pixels but without any colors and is in some gray mode! Our further investigation shows that ''summing to grayscales'' (AH=0x12, BL=0x33, Int10h) is active! And it’s impossible to deactivate it. To set up the VGA pallet and color register again by Bios system calls has no effects.

Now, what does the VGA-Bios do? What does 1-L & 3-S beeps mean in Elpin Systems VGA-Bios? (They have unfortunately not answered to my mail.) and why does it sometimes initialize the system in gray mode?

Our system has 32MB of SDRAM, 4MB as frame buffers and the rest as system memory.

Best regards,

/Babak