AVR JTAG Interface with USB

A specialized FT2232 chip with two independent channels is used by this AVR JTAG interface where one is use for simple serial communication between target and PC and one is used for JTAG.

The project was constructed in order to implement JTAG interface into target AVR system and use USB to debug it remotely without specific JTAGICE hardware. To integrate FT2232 in target board is the main idea and for all communication such as serial, JTAG, or SPI, the USB interface is used as standard target board interface.

The PC application covers all logic by having two connections through USB to target and through TCP to AVR Studio. To process JTAG and SPI data interchange, all commands are interpreted to FT2232 commands and sent to the target FT2232 chip. There are two modes in this PC software. An independent software runs on the first mode wherein the connection through JTAG or SPI, read signature, reset target, software download, and manage target fuses are supported. The AVR Studio mode is the second mode wherein the PC software interprets AVR Studio requests and communicates via JTAG or SPI with target by operating as JTAGICEMK2 emulation.

Rest of the project