Intel Assabet ARM NTSC Video

This page has some brief information and completely undocumented hacks which attempt to force the Assabet ARM board to produce NTSC video.

I never got NTSC video to work, but I got very close. I believe some small tweeks to the video controller should make it work. I did not, however, write any code to allow normal /dev/fb access to the new NTSC video format. The pixel format changes from rgb to UV space and the pixels are encoded in a different format. Running in NTSC mode requires two fields (this is interlaced video) and the frame buffer map is different.

I found most of the helpful information in the Intel v2.x diagnostic code for the Assabet. The v1.x diagnostics didn't have any code to support NTSC.

• user space hacks
• kernel files for linux-2.4.0-test9-rmk1-np2

user space hacks

• bars.c
  produce various known patterns on the display; verifies frame buffer operation and is fun to look at

• i2c.c
  uses a hack in the kernel driver to send i2c commands to the ADV7176 chip and the video h/w in the SA1110. Useful for changing the video h/w regs in real time to test new values.

• poke.c
  an attempt to poke to video h/w using mmap. didn't work, but I think the problem was just that it needed an additional flag in the open call (O_SYNC? that should make it non-cached)

• utv.c grabbed frames from the usb video capture and wrote them to the fb.

kernel hacks

• frame buffer
  Make changes to sizing and initialization of video hardware

• i2c
  Added support for Assabet i2c bus for control of the Analog Devices video encoder chip.