Tiny AVR Programmer In stock PGM-11801 won't support I2C

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1

I bought the iny AVR Programmer In stock PGM-11801 thinking I could use it for on-target development using I2C as shown in this photo: https://cdn.sparkfun.com/r/600-600/asse … 8b456a.png

After trying several devices and I2C libararies I became convinced this would not work, and moving the programmed ATTiny85 to a breakout board confirmed it. The method shown to attach target hardware to some IO pins no doubt works but in my opinion, the “Hook Up Guide” is misleading because it fails to point out that some applications like I2C (using the USI_TWI library or direct big-banging) will not work due to the other stuff that is attached to P2 and P0.

Posting this just in case it saves someone else a few hours of head-scratching!

Bob

2

Ahh… that makes sense; the SDA and SCL lines are connected to the SPI pins on the ATtiny84, used to program the chip. I’ll add a note to the hookup guide for other users. Thanks for the heads up.