ATMega32 JTAG Fuse

A new ATmega32 chip has a working JTAG interface enabled by default.

The JTAG interface shares the Port C pins, and I plan to use port C for normal I/O operation, therefore I need to disable JTAG. This page shows how to do this.

When the controller boots, it performs a boundary scan for the JTAG pins, and sometimes it can mistake other devices connected to the C port as JTAG devices and remain there in a loop. Therefore, it is a good idea to disable JTAG when using port C for normal I/O operations to prevent losing connection with the chip.

However, if you are not using any of the port C pins at all, then it is a good idea to leave the JTAG support in place.

To disable JTAG the settings are:

JTAG Fuse "unprogrammed" (binary 1) (unchecked)

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