Re: [uCsimm] LCD connected, now what ???

From: Johan Severeyns (js@idcs.be)
Date: Sat Sep 16 2000 - 11:53:58 EDT


Hi Tom,

Tom Walsh wrote:

> Try something like this:
>
> void SetupLCD (void)
> {/* set scan rate, etc. */
> Frame1 = (BYTE *) malloc (FrameSize);
> /* turn LCD off. */
> *(vBytePtr) LCKCON_ADDR = 0x0; /* LCD Clocking Control Register. */
> *(vBytePtr) LVPW_ADDR = 0x14; /* LCD Virtual Page Width Register. */
> *(vWordPtr) LXMAX_ADDR = 640; /* LCD Screen Width Register. */
> *(vWordPtr) LYMAX_ADDR = 240; /* LCD Screen Height Register. */
> *(vBytePtr) LRRA_ADDR = 0x70; /* LCD refresh rate. */
> *(vBytePtr) LPXCD_ADDR = 1; /* LCD Pixel Clock Divider Register. */
> *(vBytePtr) LPICF_ADDR = 8; /* LCD Panel Interface Config Register. */
> *(vBytePtr) LPOLCF_ADDR = 0xf; /* LCD Polarity Configuration Register.
> */
> *(vWordPtr) PCPDEN_ADDR = 0xff00; /* LCD pins Port C Pull-Down enb. reg
> */
> *(vIntPtr) LSSA_ADDR = (int) Frame1; /* LCD starting address. */
> /* turn LCD back on. */
> *(vBytePtr) LCKCON_ADDR = 0x80; /* LCD Clocking Control Register. */
> }

You mean user space here, not kernel source, right ?
Since you initialize the LCD controller here, there is no need any more
to modify the kernel 'crt0_rom.S' or to set environment variables from
the boot loader, right ?
Did you try the above code on your display ?

>
> I got an image on the display for about 1 second of power-on before the
> display went blank. No clue as to what is wrong, there may be some
> funky initialization that has to be done to immediately after power-on
> and before it can be used? Maybe something like "wiggle these clock
> lines this way..." or "stuff these bytes into it first..."???

Do you mean garbage on the display or a real image ? Mine shows some
garbage that dissapears after a little while, at power-on.

> You can find the area to change these values in
> linux/arch/m68knommu/platform/68EZ328/ucsimm/crt0_rom.S, you may need to
> tinker with the LPOLCF register values, these control the polarity of
> the clock, etc., signals.
>
> TomW
>
> BTW. My backlight is a bit dim, how is yours? The display is a 3.3v
> display, not a 5v unit!

Yep, the same here, but I think this is normal for a low power EL backlight
like this. After all it seems like a PDA display to me, which explains the low
power consumption (approx 80mA).

>
> --
> Tom Walsh - WN3L - Embedded Systems Consultant
> 'www.openhardware.net', 'www.cyberiansoftware.com'
> "Windows? No thanks, I have work to do..."
> This message resent by the ucsimm@uclinux.com list server http://www.uClinux.com/

--
 Johan Severeyns
 R&D Engineer, Network Administrator
 IDCS N.V.

This message resent by the ucsimm@uclinux.com list server http://www.uClinux.com/



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