We have some problems with the last Linux version, because the pixel clock is too high. So sometimes you get some pixel errors. But only on the 7" display. You can download the last Zimage for the 7" version (20090526) in the download section, there is the problem fixed. Or you can change: In the file linux-2.6.29/arch/arm/mach-s3c2440/mach-mini2440.c The line 96 LCD_PIXCLOCK to 40000
My board is arrived today. This a mini2440 equipped a 7" touch screen. I played with it a little and found there is a problem with some pixels on some of the (pre-installed) Qtopia tabs. This looks like this: on one tab (say, Applications) the whole screen looks good and I see no problem pixels, but when I switch to another tab (say, Friendly Arm) some pixels become trembling, flashing and shifting from their places to the right border of the screen. I also noticed the flashing pixels change their view when I touch the short cable on back of the screen board, I wonder if this a result of the overclocking described above or a hardware problem? Has anybody else experienced this? Another problem is the touch screen. There is a problem with Qtopia's cursor trembling. I just put my stylus somewhere on the screen and keep it immovable. While I do this I can see the cursor in Qtopia trembles hardly so I even can't enter a symbol on the hand writing keyboard. Could anybody please let me know if this is how these things should be or there is a problem with the touch screen? Thanks.
For the last problem can you open and run any of the programs under the Settings tab? I found on my 3.5" unit that using 0x30000000 as a start address for DNW downloads (using SuperVivi) seemed to cause "trembling" (as well as not opening those apps). I changed to 0x32000000 as seen in uBoot implementations and everything is fine again.
Thank you, I will try other images and start addresses. But what about the touch screen? Do you experience the cursor trembling when you keep your stylus on the same place?
OK, I just realized you was talking about the last problem. Well, yes, I can confirm that otherwise the touch screen works OK.
After upgrading the Linux kernel the trembling pixels disappeared, so I conclude that was a software issue (probably the overclocking noted in the first post of the thread). The problem with the touch screen is still here, and due to the problem with large supervivi images I can't try Windows CE to see how the touch screen work with it.
Hey, I am having the same issue you described Higgins, I just got the screen and I havent tried any other OS yet, however it certainly seems to be a problem with the controller not refreshing the screen correctly since it should refresh the same image constantly. I plan on trying WinCE and updating qtopia drivers (andahammer.com) "Qtopia: New August 23 build from FriendlyARM. Huge improvement in 7" touch pad. Solves some vexing video problems. Kernels for NEC and Toppoly 3.5" LCDs. All new Mini35s will have the Toppoly LCD. " hopefully one of those will work and if they do I will update.
Please do. Thanks.
Hey that did it, I followed the instructions for updating the bootloader on www.andahammer.com (JTAGingTHENor.pdf) pretty straight forward instruction set and the screen is behaving normally now, no trembling/flashing pixels on the right side of the screen. I am assuming that the problem was in the kernel and just needed to be updated.
OK, happy to know that worked for you. Now I would like to try the touch pad improvements. But where I could download this updated version of Qtopia?