Electronic – Serial Programming and I2C port “conflict”

attinyattiny85i2cisp

I'm designing a board in which an Attiny85 is connected to an accelerometer (MPU-6050) via I2C.

The I2C pins are in the ISP bus (SDA/MOSI, SCL/SCK). I wonder what happens to the accelerometer during programming of the MCU?

Are there any best practices I should follow? I considered just adding some solder jumpers, but I wonder if any precaution is even necessary.

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Edit:

After finding out this is problematic, I'll try a solution based on Bruce Abbotts answer in another question.

Best Answer

The MPU-6050 may prevent you from programming the ATTiny successfully. It would interpret the ISP data as I²C and react accordingly. Expect interesting behaviuor on both SCL and SDA lines.

During programming the SCL and SDA should be disconnected from the Tiny MCU, e.g. by jumpers or dip switches.

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