LCD controller issue

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ianscriven
Posts: 18
Joined: Wed Nov 25, 2009 4:15 am

LCD controller issue

Mon Mar 22, 2010 9:32 am

Hi,

I'm running an 800x600 OLED display using the at91sam9263 micro and an AD7125 DAC. Everything seems to work, although any significant activity on the display causes an error in the LCDC (display flashes, "IT LCDC" is re-printed to the debug serial port). Moving the mouse around doesn't cause this, although right clicking on the desktop to bring up the menu does. Moving between items on this menu sometimes causes the problem.

Any ideas? I'm thinking it's possibly a memory problem. I'm not using directdraw, so it shouldn't matter that my VRAM height isn't more than double my display height?

My lcdc.reg:

Code: Select all

[HKEY_LOCAL_MACHINE\System\GDI\ROTATION]
   "Angle"=dword:0


; Video driver settings
[HKEY_LOCAL_MACHINE\Drivers\Display\LCDC]
;800x600x16
   "Width"=dword:320              ; Screen width in pixel
   "Height"=dword:258             ; Screen heigth in pixel
   "Bpp"=dword:10                 ; Bit per pixel
   "VRAMWidthInPixel"=dword:400   ; Frame buffer width in pixel (must be at least screen width value and also must match the 2DGE settings. keeping it aligned on 4 bytes allows not to care about the later)
   "VRAMHeightInPixel"=dword:400 ; Frame buffer heigth in pixel (must be at least screen height and more than twice for directdraw)
   "VRAMaddress"=dword:23e00000    ; Frame buffer location. Here allocate the video memory in SDRAM
   "VRAMBusWidth"=dword:20         ; SDRAM has a 32-bits bus width
;   "VRAMaddress"=dword:300000      ; allocate the video memory in SRAM
;   "VRAMBusWidth"=dword:20         ; SRAM has a 32-bits bus width
;   "VRAMaddress"=dword:70000000   ; allocate the video memory in external PSRAM
;   "VRAMBusWidth"=dword:10         ; external PSRAM has a 16-bits bus width
   "DisplayPowerClass"=multi_sz:"{EB91C7C9-8BF6-4a2d-9AB8-69724EED97D1}"
;   "forceRGB"=dword:1           ; uncomment this line if you want to use DirectDraw,
                                ; be careful, the color will be shifted
   
   "UpperMargin"=dword:19          ; Value for Vertical Back Porch
   "LowerMargin"=dword:1          ; Value for Vertical Front Porch
   "LeftMargin"=dword:58           ; Value for Horizontal Back Porch
   "RightMargin"=dword:28         ; Value for Horizontal Front Porch
   "Vsync"=dword:3                ; Value for Vertical Synchronization pulse width
   "Hsync"=dword:80                ; Value for Horizontal synchronization pulse width
   "PixelClock"=dword:2625A00      ; The pixel clock wanted

[HKEY_LOCAL_MACHINE\system\gdi\monitors]
   "TOTAL MONITORS"=dword:1

[HKEY_LOCAL_MACHINE\System\GDI\Drivers]
    "Display"="at91sam9263ek_DDI.dll"
ianscriven
Posts: 18
Joined: Wed Nov 25, 2009 4:15 am

Re: LCD controller issue

Fri Mar 26, 2010 6:36 am

Ok I've worked this out - the pixel clock was too high, and I was getting FIFO underflows.

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