Microchip Technology Power Debugger Manual page 62

...........continued
Name AVR
PORT
Pin
GND 2, 10
4.3.4 aWire Physical Interface
The aWire interface makes use of the RESET wire of the AVR device to allow programming and debugging functions.
A special enable sequence is transmitted by the Power Debugger, which disables the default RESET functionality of
the pin.
When designing an application PCB, which includes a Microchip AVR with the aWire interface, it is recommended to
use the pinout as shown in
the cabling and adapters included with the particular kit.
Figure 4-8. aWire Header Pinout
Tip:
Since aWire is a half-duplex interface, a pull-up resistor on the RESET line in the order of 47kΩ is
recommended to avoid false Start bit detection when changing direction.
The aWire interface can be used as both a programming and debugging interface. All features of the OCD system
available through the 10-pin JTAG interface can also be accessed using aWire.
4.3.5 Connecting to an aWire Target
The aWire interface requires only one data line in addition to V
line, although the debugger uses the JTAG TDO line as the data line.
The recommended pinout for the 6-pin aWire connector is shown in
Connection to a 6-pin 100-mil aWire Header
Use the 6-pin 100-mil tap on the flat cable (included in some kits) to connect to a standard 100-mil aWire header.
Connection to a 6-pin 50-mil aWire Header
Use the adapter board (included in some kits) to connect to a standard 50-mil aWire header.
Connection to a custom 100-mil Header
The 10-pin mini-squid cable should be used to connect between the Power Debugger AVR connector port and the
target board. Three connections are required, as described in the table below.
Table 4-8. Power Debugger aWire Pin Mapping
Power Debugger AVR PORT Pins
Pin 1 (TCK)
Pin 2 (GND)
Pin 3 (TDO)
Pin 4 (VTG)
Pin 5 (TMS)
©
2020 Microchip Technology Inc.
SAM
PORT
Pin
3, 5, 9 Ground. All must be connected to ensure that the Power Debugger and the target
device share the same ground reference.
Figure 4-8. Both 100-mil and 50-mil variants of this pinout are supported, depending on
(RESET_N) DATA
Description
1 2
VCC
(NC)
(NC)
(NC) GND
aWire
and GND. On the target this line is the nRESET
CC
Figure 4-8.
Target Pins Mini-Squid Pin
1
GND 2
DATA 3
VTG 4
5
User Guide
Power Debugger
On-chip Debugging
aWire Pinout
6
1
2
DS40002201A-page 62