Dear colleagues, I'm trying to interface Casio 3,5" TFT display (COM35T3193KTC) to Epson S1D13705 controler and Freescale MC56F8366 DSP. After a day of timing configuring everything seems to be OK but I have one big problem with display contrast and colors - it's not possible to display whole black screen. When I fill screen with white colour It's possible to display only very narrow colour bars (width about 20 pixels, height is unlimited) without colour defects. When bar width is increased contrast is bad and if width is nearly 320 px colors are inverted. I've measured all voltages generated by display (-12V, 12V and others) and it's OK except VDD2 (5,65V and datasheet says 4,8V in timing diagram, not defined in any DC characteristics). I really don't know how to continue in my project. Thank you for any help.
TFT contrast problem
Started by ●April 23, 2008
Reply by ●April 23, 20082008-04-23
In comp.arch.embedded, hapedo <phapal@viditech.cz> wrote:> Dear colleagues, > I'm trying to interface Casio 3,5" TFT display (COM35T3193KTC) to Epson > S1D13705 controler and Freescale MC56F8366 DSP. After a day of timing > configuring everything seems to be OK but I have one big problem withHow did you configure timing? We did a 13706 using epson's configuration utility and found that will not output the correct value for the pixel clock divider, resulting in pck=clkin. Hand check all output values from that utility if you use something simular. -- Stef (remove caps, dashes and .invalid from e-mail address to reply by mail) Vuiodh qeoh jh wdhf poqufmnv alkhf adsfoj ad? Hjiyu qsdiyupq dff asdf!
Reply by ●April 23, 20082008-04-23
>In comp.arch.embedded, >hapedo <phapal@viditech.cz> wrote: >> Dear colleagues, >> I'm trying to interface Casio 3,5" TFT display (COM35T3193KTC) toEpson>> S1D13705 controler and Freescale MC56F8366 DSP. After a day of timing >> configuring everything seems to be OK but I have one big problem with > >How did you configure timing? We did a 13706 using epson's configuration >utility and found that will not output the correct value for the pixel >clock divider, resulting in pck=clkin. Hand check all output values from >that utility if you use something simular. > > >-- >Stef (remove caps, dashes and .invalid from e-mail address to reply bymail)> >Vuiodh qeoh jh wdhf poqufmnv alkhf adsfoj ad? Hjiyu qsdiyupq dff asdf! >Thanks for reply. I've used Epson's config utility too. CLKI = 6,25MHz, pixel clock = CLKI, frame rate = 50Hz (512 clocks per line). I've measured all signals by scope and it's ok. I think there is some problem with panel. I have only one panel for my prototype board. Is there some possibility that panel was degraded during firmware developement? Panel is 24 bit and s1d13705 12 bit only - I have R G and B LSBs grounded.
Reply by ●April 23, 20082008-04-23
On Apr 23, 7:27=A0am, "hapedo" <pha...@viditech.cz> wrote:> Dear colleagues, > I'm trying to interface Casio 3,5" TFT display (COM35T3193KTC) to Epson > S1D13705 controler and Freescale MC56F8366 DSP. After a day of timing > configuring everything seems to be OK but I have one big problem with > display contrast and colors - it's not possible to display whole black > screen. When I fill screen with white colour It's possible to display only=> very narrow colour bars (width about 20 pixels, height is unlimited) > without colour defects. When bar width is increased contrast is bad and if=> width is nearly 320 px colors are inverted. I've measured all voltages > generated by display (-12V, 12V and others) and it's OK except VDD2 (5,65V=> and datasheet says 4,8V in timing diagram, not defined in any DC > characteristics). I really don't know how to continue in my project. Thank=> you for any help.You say you are looking at a narrow color bars but the height is unlimited. So you have about 20 pixels of color and no activity on rest of the panel? Is your memory mapped correctly? I would make sure the configuration is correctly set. I have worked on S1D13A05 and you will have to check the signals on the scope to make sure all the timings are right. The data sheet for that module has timing diagrams and that will help you set up the correct values. The configuration utility was not able to give us precise values. Suresh M. Shenoy
Reply by ●April 23, 20082008-04-23
>On Apr 23, 7:27=A0am, "hapedo" <pha...@viditech.cz> wrote: >> Dear colleagues, >> I'm trying to interface Casio 3,5" TFT display (COM35T3193KTC) toEpson>> S1D13705 controler and Freescale MC56F8366 DSP. After a day of timing >> configuring everything seems to be OK but I have one big problem with >> display contrast and colors - it's not possible to display whole black >> screen. When I fill screen with white colour It's possible to displayonly=> >> very narrow colour bars (width about 20 pixels, height is unlimited) >> without colour defects. When bar width is increased contrast is bad andif=> >> width is nearly 320 px colors are inverted. I've measured all voltages >> generated by display (-12V, 12V and others) and it's OK except VDD2(5,65V=> >> and datasheet says 4,8V in timing diagram, not defined in any DC >> characteristics). I really don't know how to continue in my project.Thank=> >> you for any help. > >You say you are looking at a narrow color bars but the height is >unlimited. So you have about 20 pixels of color and no activity on >rest of the panel? >Is your memory mapped correctly? I would make sure the configuration >is correctly set. I have worked on S1D13A05 and you will have to check >the signals on the scope to make sure all the timings are right. The >data sheet for that module has timing diagrams and that will help you >set up the correct values. The configuration utility was not able to >give us precise values. > >Suresh M. Shenoy >No, panel is mapped correctly - I'm able to draw any pixel i want. The problem is following: If I draw very short horizontal line (i.e. 20px long) the color of the line is correct. But if the line is bigger (100px or more) color starts to change - It's loosing contrast. If the line is more than 200px long color of the whole TFT panel row starts to be inverted. The result is that It's not possible to fill display with black colour because black changes to white. It's possible to draw only very narrow black bars from top to bottom (over all 240 lines), but when width is increasing black changes to grey. I'll will make and upload some photos to my FTP server.
Reply by ●April 23, 20082008-04-23
>>On Apr 23, 7:27=A0am, "hapedo" <pha...@viditech.cz> wrote: >>> Dear colleagues, >>> I'm trying to interface Casio 3,5" TFT display (COM35T3193KTC) to >Epson >>> S1D13705 controler and Freescale MC56F8366 DSP. After a day of timing >>> configuring everything seems to be OK but I have one big problem with >>> display contrast and colors - it's not possible to display wholeblack>>> screen. When I fill screen with white colour It's possible to display >only= >> >>> very narrow colour bars (width about 20 pixels, height is unlimited) >>> without colour defects. When bar width is increased contrast is badand>if= >> >>> width is nearly 320 px colors are inverted. I've measured allvoltages>>> generated by display (-12V, 12V and others) and it's OK except VDD2 >(5,65V= >> >>> and datasheet says 4,8V in timing diagram, not defined in any DC >>> characteristics). I really don't know how to continue in my project. >Thank= >> >>> you for any help. >> >>You say you are looking at a narrow color bars but the height is >>unlimited. So you have about 20 pixels of color and no activity on >>rest of the panel? >>Is your memory mapped correctly? I would make sure the configuration >>is correctly set. I have worked on S1D13A05 and you will have to check >>the signals on the scope to make sure all the timings are right. The >>data sheet for that module has timing diagrams and that will help you >>set up the correct values. The configuration utility was not able to >>give us precise values. >> >>Suresh M. Shenoy >> >No, panel is mapped correctly - I'm able to draw any pixel i want. The >problem is following: If I draw very short horizontal line (i.e. 20pxlong)> the color of the line is correct. But if the line is bigger (100px or >more) color starts to change - It's loosing contrast. If the line ismore>than 200px long color of the whole TFT panel row starts to be inverted.The>result is that It's not possible to fill display with black colourbecause>black changes to white. It's possible to draw only very narrow blackbars>from top to bottom (over all 240 lines), but when width is increasingblack>changes to grey. I'll will make and upload some photos to my FTP server. >Here are some photos. Sorry for bad quality - made by mobile phone. Here you can see, how color changes with number of painted pixels on line. http://hap.namest.net/tft/1.jpg http://hap.namest.net/tft/2.jpg http://hap.namest.net/tft/3.jpg http://hap.namest.net/tft/4.jpg And here is TFT datasheet http://hap.namest.net/tft/tft_casio.pdf There is 512 clocks per line (in datasheet). Isn't it too much? Is there some possibility that one line is driven for a very long time (all timings were measured by scope and are OK - PCLK 6.25MHz, line frequency 12kHz, frame rate 50Hz)? I can post here register setup of S1D13705 and TFT panel. Thank you for any help.
Reply by ●April 23, 20082008-04-23
suresh shenoy wrote:> "hapedo" <pha...@viditech.cz> wrote: >> >> I'm trying to interface Casio 3,5" TFT display (COM35T3193KTC) >> to Epson S1D13705 controler and Freescale MC56F8366 DSP. After >> a day of timing configuring everything seems to be OK but I have >> one big problem with display contrast and colors - it's not >> possible to display whole black screen. When I fill screen with >> white colour It's possible to display only very narrow colour >> bars (width about 20 pixels, height is unlimited) without >> colour defects. When bar width is increased contrast is bad and >> if width is nearly 320 px colors are inverted. I've measured >> all voltages generated by display (-12V, 12V and others) and >> it's OK except VDD2 (5,65V and datasheet says 4,8V in timing >> diagram, not defined in any DC characteristics). I really don't >> know how to continue in my project. Thank you for any help. > > You say you are looking at a narrow color bars but the height is > unlimited. So you have about 20 pixels of color and no activity > on rest of the panel? > > Is your memory mapped correctly? I would make sure the > configuration is correctly set. I have worked on S1D13A05 and > you will have to check the signals on the scope to make sure > all the timings are right. The data sheet for that module has > timing diagrams and that will help you set up the correct > values. The configuration utility was not able to give us > precise values.This is only a guess, I am not at all familiar with your hardware. I suspect that something in the display is AC coupled, and trying to restore the average illumination level. From your description that something is line based. -- [mail]: Chuck F (cbfalconer at maineline dot net) [page]: <http://cbfalconer.home.att.net> Try the download section. ** Posted from http://www.teranews.com **
Reply by ●April 24, 20082008-04-24
On Apr 23, 1:13=A0pm, "hapedo" <pha...@viditech.cz> wrote:> >>On Apr 23, 7:27=3DA0am, "hapedo" <pha...@viditech.cz> wrote: > >>> Dear colleagues, > >>> I'm trying to interface Casio 3,5" TFT display (COM35T3193KTC) to > >Epson > >>> S1D13705 controler and Freescale MC56F8366 DSP. After a day of timing > >>> configuring everything seems to be OK but I have one big problem with > >>> display contrast and colors - it's not possible to display whole > black > >>> screen. When I fill screen with white colour It's possible to display > >only=3D > > >>> very narrow colour bars (width about 20 pixels, height is unlimited) > >>> without colour defects. When bar width is increased contrast is bad > and > >if=3D > > >>> width is nearly 320 px colors are inverted. I've measured all > voltages > >>> generated by display (-12V, 12V and others) and it's OK except VDD2 > >(5,65V=3D > > >>> and datasheet says 4,8V in timing diagram, not defined in any DC > >>> characteristics). I really don't know how to continue in my project. > >Thank=3D > > >>> you for any help. > > >>You say you are looking at a narrow color bars but the height is > >>unlimited. So you have about 20 pixels of color and no activity on > >>rest of the panel? > >>Is your memory mapped correctly? I would make sure the configuration > >>is correctly set. I have worked on S1D13A05 and you will have to check > >>the signals on the scope to make sure all the timings are right. The > >>data sheet for that module has timing diagrams and that will help you > >>set up the correct values. The configuration utility was not able to > >>give us precise values. > > >>Suresh M. Shenoy > > >No, panel is mapped correctly - I'm able to draw any pixel i want. The > >problem is following: If I draw very short horizontal line (i.e. 20px > long) > > the color of the line is correct. But if the line is bigger (100px or > >more) color starts to change - It's loosing contrast. If the line is > more > >than 200px long color of the whole TFT panel row starts to be inverted. > The > >result is that It's not possible to fill display with black colour > because > >black changes to white. It's possible to draw only very narrow black > bars > >from top to bottom (over all 240 lines), but when width is increasing > black > >changes to grey. I'll will make and upload some photos to my FTP server. > > Here are some photos. Sorry for bad quality - made by mobile phone. Here > you can see, how color changes with number of painted pixels on line.http:=//hap.namest.net/tft/1.jpghttp://hap.namest.net/tft/2.jpghttp://hap.namest.n= et/tft/3.jpghttp://hap.namest.net/tft/4.jpg> And here is TFT datasheethttp://hap.namest.net/tft/tft_casio.pdf > There is 512 clocks per line (in datasheet). Isn't it too much? Is there > some possibility that one line is driven for a very long time (all timings=> were measured by scope and are OK - PCLK 6.25MHz, line frequency 12kHz, > frame rate 50Hz)? I can post here register setup of S1D13705 and TFT panel=.> Thank you for any help.- Hide quoted text - > > - Show quoted text -I see the problem. Could you verify the value at these memory locations? Make sure you are reading the same values you write. If for instance FF is black in your color pallete and you write it to mem loc x10 then when you read it, it should be x10. If not then there is an issue. If you confirm that the data are the same then i suspect panel might have some other issue. You also mentioned something regarding 12bit s1d13705 and 24bit chip. I think you should investigate this is set up right. There are some bit shift mechanism to get the correct color. If this is set wrong we could also notice the behavior you are seeing. Suresh M. Shenoy
