on the strange behavior of a damaged FPGA... a cautionary tale:)
rjo__
Posts: 2,114
in Propeller 2
I've been reading about Peter's strange problems... and as fate would have it, I started to have the same problem...
What worked for previous incantations of the P2 wasn't working on v27, but with a twist. I know what happened.
While working away in v27, an OV7675 camera board at 3.3v from a variable power supply, my camera board developed a short. I know it shorted because I could smell it. It stopped sending images, and the variable power supply hooked up to it showed 0V... that is zero as in zero volts, not OV as in Omnivision:)
I plugged a fresh camera board in and by golly it didn't work either. No smoke or anything, just couldn't seem to get a vertical sync to save its life. I went back to Pv12... and after moving jumpers around, I was back in business. The only thing is... the exact same code won't work with Pv27a, even though it had before. No vertical sync, which remained on exactly the same pin that works for Pv12.
My conclusion is that the fabric which connects to the pins differs between Chips various incantations.
A damaged fabric might affect one version of the P2 but not another.
Case closed. Time for a drink.
What worked for previous incantations of the P2 wasn't working on v27, but with a twist. I know what happened.
While working away in v27, an OV7675 camera board at 3.3v from a variable power supply, my camera board developed a short. I know it shorted because I could smell it. It stopped sending images, and the variable power supply hooked up to it showed 0V... that is zero as in zero volts, not OV as in Omnivision:)
I plugged a fresh camera board in and by golly it didn't work either. No smoke or anything, just couldn't seem to get a vertical sync to save its life. I went back to Pv12... and after moving jumpers around, I was back in business. The only thing is... the exact same code won't work with Pv27a, even though it had before. No vertical sync, which remained on exactly the same pin that works for Pv12.
My conclusion is that the fabric which connects to the pins differs between Chips various incantations.
A damaged fabric might affect one version of the P2 but not another.
Case closed. Time for a drink.
Comments
Rjo__, you are using a Prop123-A9, right?
V27 was fine until I smoked my camera board ... just to see what would happen:) It was supposed to be at around 2.8v... I put in 3.3v. It has some unlabeled chips that I just assumed would handle the voltage. I'm thinking they didn't. ''
From my perspective, the P2 is perfect... except making sure it handles the USB stuff like a champ.
I wanted a chance to rant:)
Look at the code it takes to run the cameras... nothing. Then look at the code it takes one of those duinos... I don't understand how a sane person would not want to take the P2 path.
Who would buy a P2? ????
Any person not needing some form of therapy.
I have one ov7675 still in original packaging. If you or Rayman are interested it would be a lot faster for me to send it out than to wait on China.
rjo12345@hotmail.com
The camera boards I have are higher resolution, but cost $20...
I thought one had to configure with I2C to get output...
Yes no i2c here, just confuses the natives:) Works fine.
I'm going to have to do i2c to set the pll's and get the ov7675 up to 240FPS(160x120). But to tell you the truth I really don't why the board failed and I'm a little gun shy right now. I know these boards don't match the specs in some regards, and I'm a little concerned that they might just fail all by themselves... I'm thinking about playing with Parallax's new continuous rotation feedback servos first.
Summary: I2c is hooked up, just not using it.
The good stuff (register settings) is available over in the Arducam world. I even wrote a program to translate the register settings into P1 readable code... that was a real long time ago:)
If you get I2C going, please share:) At the time, I had only a passing understanding of it all, and basically hacked Phil's code to get it to do what I wanted.
I hooked up my P1 to drive the I2C and results were interesting... on the OV7675,,, the qVGA is not exactly what it should be giving a bad aspect ratio on the image... you can fix this by simply doubling the pixel writes to the HUB ram... two pixels consecutive for every pixel you capture.
I toyed with controlling the VREF start and stop... looks like it works as advertised. That was all before the 7675 images started to roll and my grandson returned to the house:)
Right now, it just reads the MSB of Manufacturer ID and sends to serial port...
BTW: it requires pull up on both i2c lines
That was a loud laugh ! Thanks !