Microchip Technology Atmel-ICE User Manual page 21

Figure 4-1. JTAG Interface Basics
4.2.2.1 SAM JTAG Pinout (Cortex
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. Both 100-mil and 50-mil variants of this pinout are supported, depending
on the cabling and adapters included with the particular kit.
Figure 4-2. SAM JTAG Header Pinout
Table 4-1. SAM JTAG Pin Description
Name Pin
TCK 4
TMS 2
TDI 8
TDO 6
nRESET 10
VTG 1
GND 3, 5, 9
KEY 7
Tip: Remember to include a decoupling capacitor between pin 1 and GND.
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2020 Microchip Technology Inc.
Programmer/
debugger
®
-M debug connector)
VCC
GND
GND
(KEY)
GND
SAM JTAG
Test Clock (clock signal from the Atmel-ICE into the target device)
Test Mode Select (control signal from the Atmel-ICE into the target device)
Test Data In (data transmitted from the Atmel-ICE into the target device)
Test Data Out (data transmitted from the target device into the Atmel-ICE)
Reset (optional). Used to reset the target device. Connecting this pin is recommended since
it allows the Atmel-ICE to hold the target device in a Reset state, which can be essential to
debugging in certain scenarios.
Target voltage reference. Atmel-ICE samples the target voltage on this pin to power the
level converters correctly. The Atmel-ICE draws less than 1 mA from this pin in this mode.
Ground. All must be connected to ensure that the Atmel-ICE and the target device share the
same ground reference.
Connected internally to the TRST pin on the AVR connector. Recommended as not
connected.
Programmers and Debuggers
TCK
TMS
TDI
TDO
1 2
TMS
TCK
TDO
TDI
nRESET
Description
User Guide
On-Chip Debugging
Vcc
Target
device
DS50002999A-page 21