This is a continuation of Part 1Now we solder some very fine wires to the ends of the 0402 resistors on the camera's I2C bus. You can see an american penny in the image for scale.Now we can use a multimeter to probe the pins on the A13 to find out which pins the camera's I2C bus are connected to.Interesting...Probing has not gone as expected and the two locations which I thought were I2C lines do not seem to be directly connected to the pins on the A13 CPU. OK, time to do some systematic checking of the pins. From the configuration file for the tablet, it looks like the following pins should be connectedAs best as I can figure out after probing with a multimeter for two hours, the pins from the camera connector (pin 1 nearest the edge of the pcb) are connected to the following:Which means I have soldered wires to the wrong place. It looks like the I2C pullup resistors are actually located very close the the CPU. It's going to be a tight squeeze, but what can you do.Here is a shot of the correct placement of the I2C debug wires on the pullup resistors next to the CPU.On a side note, I think my tablet may have counterfeit memory chips (not really surprised). I had electrical tape over the memory chips to hold down some wires and when I removed the tape, the markings came off the chips and stuck to the electrical tape.
DISASTER! I seem to have broken something. I suspect when I pulled the tape off the DDR RAM, it broke a solder joint underneath the chip. All I get now is
I think my only choice is to attempt to reflow the memory chip with a heat gun. That's it for now. Check in for Part 3 if I can get it working again.
DISASTER! I seem to have broken something. I suspect when I pulled the tape off the DDR RAM, it broke a solder joint underneath the chip. All I get now is
I think my only choice is to attempt to reflow the memory chip with a heat gun. That's it for now. Check in for Part 3 if I can get it working again.
Fixing the Linux Camera Driver on an AllWinner A13 Tablet (Part 2) This is a continuation of Part 1 Now we solder some very fine wires to the ends of the 0402 resistors on the camera's I2C bus. You can see an american penny in the image for scale.