4.3.3.1 PIC32M Types of JTAG

JTAG Method (PIC32M MCU):

• 2-wire JTAG: Microchip proprietary JTAG
• 4-wire JTAG: Traditional JTAG (IEEE1149.1)

What is 2-wire JTAG?

2-wire JTAG is a proprietary debug interface defined by Microchip. Based on 4-wire JTAG device internally, using a 2-wire converter that multiplexes the TMS, TDI, TDO JTAG lines to a single data line to the outside and demultiplexes it to the inside. Requires a special conversion unit in the device. On older devices, this conversion unit was only activated in case the device was in the special 2-wire programming mode, but did not allow full debugging using the 2-wire protocol.