Microchip Technology MPLAB ICD 5 - Page 22

Connecons
User Guide
© 2023 Microchip Technology Inc. and its subsidiaries
DS-50003529B - 22
Figure 3-11. JTAG Interface Basics
Vcc
TMS
TDI
TDO
TCK
Programmer/
debugger
Target
device
3.3.5.2 Connecng to a AVR JTAG Target
The MPLAB ICD 5 using the MPLAB ICD 5 ICSP Adapter Board and the AVR JTAG (10 Pin) Adapter
Board provides a legacy 10-pin 50-mil JTAG connection.
Direct Connection to a 10-pin 50-mil Header
Use the 10-pin 50-mil plugin connector on the “AVR JTAG (10 pin)” adapter board to connect directly
to a target board with headers complying with the header pinout.
3.3.5.3 AVR JTAG Pinout
When designing an application PCB, which includes an AVR with the JTAG interface, it is
recommended to use the pinout as shown in the gure below.
For other AVR connections, see 4.3. AVR Devices - On-Chip Debugging (OCD).
Figure 3-12. AVR JTAG Header Pinout
Table 3-7. AVR JTAG Pin Descripon
Name Pin Description
TCK 1 Test Clock (clock signal from the MPLAB ICD 5 into the target device).
TMS 5 Test Mode Select (control signal from the MPLAB ICD 5 into the target device).
TDI 9 Test Data In (data transmitted from the MPLAB ICD 5 into the target device).
TDO 3 Test Data Out (data transmitted from the target device into the MPLAB ICD 5).
nTRST 8 Test Reset (optional, only on some AVR devices). Used to reset the JTAG TAP controller.
nSRST 6 Reset (optional). Used to reset the target device. Connecting this pin is recommended since it allows the MPLAB
ICD 5 to hold the target device in a reset state, which can be essential to debugging in certain scenarios.
VTG 4* Target voltage reference. The MPLAB ICD 5 samples the target voltage on this pin in order to power the level
converters correctly. The MPLAB ICD 5 draws less than 1mA from this pin in this mode.
GND 2, 10 Ground. All must be connected to ensure that the MPLAB ICD 5 and the target device share the same ground
reference.
* Remember to include a decoupling capacitor between VTG and GND.