Microchip Technology Power Debugger Manual page 66

4.4.3 SPI Physical Interface
In-system programming uses the target Microchip AVR's internal SPI (Serial Peripheral Interface) to download code
into the Flash and EEPROM memories. It is not a debugging interface. When designing an application PCB, which
includes an AVR with the SPI interface, the pinout as shown in the figure below should be used.
Figure 4-10. SPI Header Pinout
4.4.4 Connecting to an SPI Target
The recommended pinout for the 6-pin SPI connector is shown in
Connection to a 6-pin 100-mil SPI Header
Use the 6-pin 100-mil tap on the flat cable (included in some kits) to connect to a standard 100-mil SPI header.
Connection to a 6-pin 50-mil SPI Header
Use the adapter board (included in some kits) to connect to a standard 50-mil SPI 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. Six connections are required, as described in the table below.
Important:
The SPI interface is effectively disabled when the debugWIRE enable fuse (DWEN) is programmed, even
if SPIEN fuse is also programmed. To re-enable the SPI interface, the 'disable debugWIRE' command
must be issued while in a debugWIRE debugging session. Disabling debugWIRE in this manner requires
that the SPIEN fuse is already programmed. If MPLAB X IDE or Atmel Studio fails to disable debugWIRE,
it is probably because the SPIEN fuse is NOT programmed. If this is the case, it is necessary to use a
high-voltage programming interface to program the SPIEN fuse.
Info:
The SPI interface is often referred to as "ISP", since it was the first in-system programming interface on
Microchip AVR products. Other interfaces are now available for in-system programming.
Table 4-11. Power Debugger SPI Pin Mapping
Power Debugger AVR PORT Pins
Pin 1 (TCK)
Pin 2 (GND)
Pin 3 (TDO)
Pin 4 (VTG)
Pin 5 (TMS)
Pin 6 (nSRST)
Pin 7 (not connected)
Pin 8 (nTRST)
Pin 9 (TDI)
©
2020 Microchip Technology Inc.
1 2
PDO/MISO VCC
SCK PDI/MOSI
/RESET GND
SPI
Figure 4-10.
Target Pins
SCK
GND
MISO
VTG
/RESET
MOSI
User Guide
Power Debugger
On-chip Debugging
Mini-Squid Pin SPI Pinout
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2
3
4
5
6
7
8
9
DS40002201A-page 66
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