28 lines by 60 columns on a NEW Ativa 7-inch photo frame
localroger
Posts: 3,452
As I recently suggested might be possible, I have written a working driver for the Ativa PF-7AW-201-P3R 7-inch digital photo frame which is currently available from Office Depot for around $39:
http://forums.parallax.com/showthread.php?129989-Looking-good-to-hack-Ativa-7-inch-photo-frame&p=981010#post981010
I will post a detailed writeup to my blog here later but for now enjoy the pix, peruse the code, and learn and some stuff I learned about these LCD's:
1. While the signals are very similar, the timing and everything else was completely different from the Philips PET 702 DVD player I recently hacked.
2. The signals give *no time at all* between the horizontal sync pulse and the first character to set up the video driver, so there is a 1-character wide border on the left side of the screen.
3. This driver emits a nonstandard frequency and number of lines, although it's in the NTSC ballpark. It doesn't give the double-line zero volt indication of vsync as the PET 702 did, but with some profiling I found a more subtle VCOM artifact that indicated vsync.
4. The video drive voltage needs to be higher; 3v3 overdrives it but 0v7 is way too low. In the picture I'm driving it at 3v3 / 2 and it could probably be a little brighter.
5. This frame has a slightly higher dot rate, about 10.3 MHz instead of 9 MHz, and my cool plan to have individual character colors within a line probably won't work without overclocking the propeller. Or you could reduce the horizontal character resolution to about 50, which opens up the timing.
6. It's 28 lines instead of 29 because the vcom artifact occurs several lines after the top of the screen. I couldn't figure out a way around this, as everything I tried destroyed sync.
The final display...
Before pix of circuit board...
...and after pix:
...and the driver: ativa_demo - Archive [Date 2011.03.06 Time 16.24].zip
http://forums.parallax.com/showthread.php?129989-Looking-good-to-hack-Ativa-7-inch-photo-frame&p=981010#post981010
I will post a detailed writeup to my blog here later but for now enjoy the pix, peruse the code, and learn and some stuff I learned about these LCD's:
1. While the signals are very similar, the timing and everything else was completely different from the Philips PET 702 DVD player I recently hacked.
2. The signals give *no time at all* between the horizontal sync pulse and the first character to set up the video driver, so there is a 1-character wide border on the left side of the screen.
3. This driver emits a nonstandard frequency and number of lines, although it's in the NTSC ballpark. It doesn't give the double-line zero volt indication of vsync as the PET 702 did, but with some profiling I found a more subtle VCOM artifact that indicated vsync.
4. The video drive voltage needs to be higher; 3v3 overdrives it but 0v7 is way too low. In the picture I'm driving it at 3v3 / 2 and it could probably be a little brighter.
5. This frame has a slightly higher dot rate, about 10.3 MHz instead of 9 MHz, and my cool plan to have individual character colors within a line probably won't work without overclocking the propeller. Or you could reduce the horizontal character resolution to about 50, which opens up the timing.
6. It's 28 lines instead of 29 because the vcom artifact occurs several lines after the top of the screen. I couldn't figure out a way around this, as everything I tried destroyed sync.
The final display...
Before pix of circuit board...
...and after pix:
...and the driver: ativa_demo - Archive [Date 2011.03.06 Time 16.24].zip
Comments
7" is the same size as my Android pad. I'm envisioning a 'Propeller Pad'...
BTW: Were you able to find any kind of datasheet for the display?
None whatsoever, although googling for any of the signal names reveals a lot of datasheets for similar products. In this case it was the labeled test points, visible in the pix of the bottom of the PC board, which got me in; I knew enough about how these things work from the PET 702 project (for which I did have a service manual) that I was able to work out the timing by experimentation. I was surprised at how different the timing turned out to be. I will be writing it up in detail by the end of the week (Tuesday is Mardi Gras, so not much gets done in New Orleans for the next couple of days LOL).
Unfortunately - the Phillips brand isn't as hackable.
I plan to get the Aptiva you mention to give it a go. Keep up the inspiring work!!
Paul
Paul
Thanks for the pointers!
Paul
OBC