LCDInfo.com

Hi

I also have a Nokia 6100 display with an Epson controller. The communication with the display is ok. I tried the initialization which was posted by Zee.
The initialization looks good, but I cannot put a pixel. My display stays always white.
Does anybody know, whats going wrong??

Thanks,
Andreas

Does the display go white only after the DISPON command? If so have you tried to put lots of pixels to the screen and look at the screen from top angle and see if the 'whiteness' alters slightly. If it does then it could just be over contrast. I have used and got working both Philips and Epson LCDs BUT every now and then I come across a so called Epson S1D15Gxx compatible display then is very very bright. So bright that the VOL UP/DOWN commands make no difference BUT I can see an image on the display if I look at the right angle. No idea yet how to reduce it.

I did experiment and lower VDD from 3.3 to 2.8 V. The display was much lower contrast but still way too bright.

I accidently disconnected 3.3V altogather and somehow the display worked fine. Good contrast etc. I guessed that the backlight voltage was perhaps being regulated onchip to 3V. However, when I toggled SCK the contrast flickered so I guess this is not the case. But weired anyway. You could confirm that yours does/doesn't do the same.

I know the exact same circuit works on tons of other S1D15Gxx and Philips PCF8833 controlled LCDs so at the moment I am attributing this problem to the LCD in question and that it perhaps uses a differnt controller or requires different voltages.

Anyone else seen this and found the reason ?

Jim

Yes the display only goes white on DISON command. And I could really see pixels on the display if I look at the screen within a special angle!!! Thanks!!!

I tried to disconect the power supply (excepting the voltage for the backlight) and while the display goes off I can see the green pixels.

But it would be very interesting why the display behaves so strange!

Andreas

Btw, how do you tell which display has what controller from whoever manufacturer?

I got two displays. One which looks the same as the one in the previous page (with the red traces) and I just can't get that to work. The other one has completely different "pcb" in it and work just fine with the S1D5G10 commands.

Wheeeeee!

That odd display finally came alive. It had the Philips PCF8833 in it. Man that has been one serious pain in the ass.

Thanks for the code Jim - I tried your initialisation. No change. I tried initialising as a philips device but that did nothing.

I played with normal/inverse and this made a change - so the device is responding!!!

I'll be well pleased when this cursed device actually works!!!

I also tried the initialization code which jimminy used in his code but it gave me a somewhat washed out display. If I removed the lines

spi(SPICommand,DISCTL); // Display Control
spi(SPIData,0x03); // Driving Pattern
spi(SPIData,0x20); // Duty
spi(SPIData,0x0c); // FRM

The display was back to normal.

It's strange isn't it. I have quite a few of the Nokia LCDs in my posession and every time I go to buy a few more they are almost always different in some way. I guess the EEPROM is stored with different factory defaults at manufacture/test time. I really don't know.

Zee: the commands you commented out are for the S1D15Gxx chips. Not the Philips. However, it maybie that you have a different 'flavor'. God knows there are lots of them. Hence why lots of people have a little struggle kicking the LCD into action. There's not always just one solution.

"I played with normal/inverse and this made a change - so the device is responding!!!
I'll be well pleased when this cursed device actually works!!! "

I know what you mean. Drives me mad everytime a different one crops up.

If the inverse makes a change. What is the change?. Darker/lighter display?. If so have you used the VOLUP command?. To check this I normally run a while loop with 50ms delay between each VOLUP command. Run the code and see if the display suddenly switches on after a while (when the contrast value rolls over). This is always my first port of call when a display looks very dark or very light. Doesn't always yield results but it's definetly a starter for 10.

Yes I know the commands are for the Epson controller, and I mentioned those just because aauer1 is having the same controller in his display.

But considering the contrast: On my Philips display the contrast makes a big difference (but without any control for it the display looks perfectly fine). On the other hand, for my Epson display, the contrast adjustent seems to have very little effect.

Ok Zee gave a clue as to why one of my displays is way too bright and the contrast Up/Down cannot get the contrast low enough [ same as aauer1 ?]. I fiddled with the duty register and hey-presto, the bright display is much lower and acceptable.

The only down side is that the contrast Up/Down commands do absolutely nothing. No change at all.

So, part way, but not quite there yet.

Any luck aauer1 ?

Ok, I also experimented with the duty register. And I get also the effect, that I can see the pictures on the display. Thats very good... but the quality of the colors is not very good.

I only get this effect if I write zero to the duty register. But there must be a futher or another option to get the display working in the right way.

Thanks for your help.
Andreas

Finally settled on the following:- Good brightness and good colors (fiddled until the color banding went away).


// For very bright washed out display (and contrast has no apparent effect. Try:
spi(SPIData,0x03); // was 0x03 // Driving Pattern
spi(SPIData,0xf1); // was 0x20 27 // Duty
spi(SPIData,0x03); // was 0x0c 1c // FRM


Jim

Ok... I think I found another way. It concerns also the DISCTL command. I wrote the following sequence:



Now, the display shows the right colors and it the VOLUP and VOLDOWN command works.

Andreas

Jim - I tried your alternate disctl values - definitely moving in the positive. The same effect was noticed with Andreas' values. The color still seems washed out. The VOLUP has an effect - I have a loop that scrolls through the values and yes, it does black out then go bright again,dims,goes black and so on....

Also, I tried removing the DISCTL command - no change from the original problem.

I'm starting to get excited - what puzzles me is how all these displays work in the Nokia phone - there must be some magic happening somewhere that we're missing!!!

I'm getting tired of recompiling and downloading my code each time, I'll have to write an interactive monitor program to make fiddling easier.