Thread: Cant get Character LCD working

What os does the other computer have?

What plugin are you using?

do you have it on the right port? (0x378, 0x278)

Did you plug it in?

Windows 98

I tried all ports... and windows IRQ/DMA are set as per Bios settings 378 7/3

Only when the lcd plugin is set to 378 i get any sort of life from the LCD whatsoever. Basically there is a highspeed scrolling going on, the whole dot matrix display lights up and appears to flash. When i pull the parallel connector out of the socket and reconnect, i see a some recognisable characters appear (like arrows, dash, and dollar signs aswell as some oriental script type characters). But this is amidst a lot of garbage and high speed scrolling. Other settings 278/3BC dont do anything.

I tried using LCDprint, BPPLCDTEST, Winamp Plugins of all sorts. Almost all of the programs say LCD not detected.

I ran a parallel port test progam.. it said an ECP printer port (LPT1) was detected at the address and irq/dma above.

The LCD works fine on a P166 machine running Windows95. And a similar LCD has run on my main Celeron (win98). I got the same results from that LCD with this mp3box as I am getting now from this LCD.

so are u using the same LCD cable in both the car/home? Also what power are u giving the LCD? is it derived from the same supply as the computer?

I would also try the mp3car LCD on your home systems again, with the same cable and all...


I think it might be that the LCD cable is too long, giving you noise.... if you can try slowing down the transmission rate from the printer port to the LCD display in your LCD plugins...

also the power you are supplying the LCD with may not be 'clean' enuff....


on a side note you say that no plugin can 'detect' the LCD? The standard LCD wiring harness from the computer to the PC can in NO WAY detect a connected LCD...... I dont know why the proggies would even say that.... hrm..?

Also check to see if there is a program or something keeping that port open.

LCDprint will say "no LCD detected" if it's not wired properly, meaning, that the program doesn't see a short or a certain sign of being there (which it can)..

I'd double check that all your wires are properly connected, and that you don't have your data lines mixed. If you don't get the 2 solid bars (line 1 and 3), when you fisrt plug it in and apply power, then something is wrong.

I've gotten the "No LCD" error, and realized that I had something connected wrong (also didn't get the black bars), and it worked great as soon as I solved the error in my soldering. So double and triple check that.

EDIT: Oh, yours is only a 2 line display... in that case, you should see the top line as solid black until you give it a signal.

Good Luck,
Miles

I will triple check my wiring again... tho ive done these lcd wireups about 4 times, this being the 6th... I think i can do this blindfolded now... lol

The cable is not long at all... about 4" actually hehe... the LCD is used in my faceplate, so it is integrated into the box. Let me illustrate with a picture: (the connector is just out of the edge of this picture)


It is part of my faceplate below:


I will check and see if perhaps my homemade PSU isnt supplying enough or clean power, though i doubt this since all my hardware runs on this psu and everything seems to work problem free. Infact audio/video has never been clearer since the switchover from a commercial dcdc (mainly due to better grounding, shielding etc).

The reason im positive that lcd is wired correct is that it works when i try it on other computers (my desktop), if it wasnt... then it technically shouldnt work on any pc.

Another long night debugging i suppose.

Thank you all for your helpful comments and taking the time to reply, i appreciate it.

I dont really have that option, there are no expansion slots and my box is 2x7x7. Im in the process of resoldering entirely... hope this works...

I hadn't seen that box before... sorry I don't know what the LCD is doing, but wanted to say cool system man.