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

From: Tom Walsh (
Date: Thu Sep 14 2000 - 11:03:13 EDT

Johan Severeyns wrote:
> Hi,
> Just got my LCD display (ALPS LRHDD1012A) connected and powered.
> Where can I find a description of what to do next to get this display running ?
> I saw some references in the mailing list to a 'crt0_rom.S' file, and the need to
> uncomment the #define LCD 1 entry, but I do not have such an entry in my file
> at all.
> Can someone help me here, please ??? Some documentation or description would
> be nice.
> Thanks in advance,
> Best Regards,
> --
> Johan Severeyns
> R&D Engineer, Network Administrator
> This message resent by the list server

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. */

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..."???

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.


BTW. My backlight is a bit dim, how is yours? The display is a 3.3v
display, not a 5v unit!

Tom Walsh - WN3L - Embedded Systems Consultant
'', ''
"Windows? No thanks, I have work to do..."
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