Error with OV6620 not ACKing

[danderson]

I am having a problem with teh OV6620 not acking. I am using a Mega128, and I am using the i2c code by John to implement the i2c interface to the OV6620. I have it hooked up to a scope and everything looks correct except for the part where the OV6620 is not acking.

It starts off with a START condition,which is good, and then SCL clocks 8 times while clocking in 0xC0 on the SDA line. On the 9th clock, SDA is supposed to be pulled low by the OV6620 to show an ACK, but it's not. Does anyone know why this would be happening?

In the code, the only thing I do (because I want to test the i2c communication first) is initialize the i2c stuff, enable interrupts, and then call the cam_config. Am I missing something?

Thank you!
Dan

[danderson]

here is a link to a drawing of what I'm seeing on the scope:

http://www.users.muohio.edu/andersd2/i2cscope.JPG

[danderson]

Also, here's an actual picture of what the scope is displaying:

http://www.users.muohio.edu/andersd2/i2ctrouble.jpg

[danderson]

Okay, so it turns out the problem was with the camera. When I tried a new camera module, it ACKed just fine.