Well I spent a few hours working on the RoboMagellan bot tonight. I didn't get much accomplished really. Much of it was setting up a work environment here in my computer room.. one of two air conditioned rooms in the house. Man it was hot today.
I modified my SPI bus. I put 180 resistors in series with the 3-axis compass. To my delight I found that the circuit still worked AND I didn't have to remove the MCU to drop a new program in. Flushed with success I went to add the accelerometer MCU to the SPI bus as well. Of course there was a problem: all my remaining Mega32's were non-responsive. I had messed up the fuse bits some way or another.
I got KJohn's STK500 up and running and recovered two previously toasted chips via high-voltage parallel programming. This was my second try at this and I was most pleased to succeed.
I added the new MCU behind another set of resistors and tried to program it live. Initially I couldn't. So I raised my resistors up to a few thousand and live programming worked. Then I realized that the other MCU was powered down. Trying again with both MCUs powered up I found the programming cycle got stuck real early in the cycle: during the initial read. Usually I get some error msg form AVR Studio, but in this configuration it just hangs.
I don't have a solution but its not a huge deal since I am using Eddy's Mega32 board and each has an independent power supply. Its a snap to just yank the battery cable on one of them. Still it would be really nice to figure out a circuit that would let me program with both live and both on the SPI bus. I'll just live with for now.
Next session I want to see if I can get some data out of the Accelerometer MCU. Should be interesting going back and forth between two bodies of code to try to get them to talk to one another!
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