SAM JTAG Pinout (Cortex®-M debug connector)

When designing an application PCB which includes a Microchip SAM with the JTAG interface, it is recommended to use the pinout as shown in the figure below.

Figure 1. SAM JTAG Header Pinout


Table 1. SAM JTAG Pin Description
Name Pin Description
TCK 4 Test Clock (clock signal from the MPLAB ICE 4 into the target device)
TMS 2 Test Mode Select (control signal from the MPLAB ICE 4 into the target device)
TDI 8 Test Data In (data transmitted from the MPLAB ICE 4 into the target device)
TDO 6 Test Data Out (data transmitted from the target device into the MPLAB ICE 4)
nRESET 10 Reset (optional). Not used by MPLAB ICE 4.
VTG 1 Target voltage reference. Not used by MPLAB ICE 4.
GND 3, 5, 9 Ground. All must be connected to ensure that the MPLAB ICE 4 and the target device share the same ground reference.
KEY 7 Connected internally to the TRST pin on the AVR connector. Recommended as not connected.
Tip: Remember to include a decoupling capacitor between pin 1 and GND.