Microchip Technology MPLAB ICD 5 - Page 23

Connecons
User Guide
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DS-50003529B - 23
3.3.5.4 AVR 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.
3.3.5.4.1 Connecng to an AVR SPI Target
The recommended pinout for the 6-pin SPI connector is shown in 3.3.5.4.2. AVR SPI Pinout.
Connection to a 6-pin 100-mil SPI Header
Use the AVR 6-pin adapter board to connect to a standard 100-mil SPI header.
Connection to a 6-pin 50-mil SPI Header
Use the AVR 6-pin mini adapter board to connect to a standard 50-mil SPI header.
Important:
The SPI interface is eectively disabled when the debugWIRE Enable (DWEN) fuse is
programmed, even if the 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 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.
Follow the instructions in the popup window that appears.
Info:
The SPI interface is often referred to as “ISP” since it was the rst in-system programming
interface on Microchip AVR products. Other interfaces are now available for in-system
programming.
3.3.5.4.2 AVR SPI Pinout
When designing an application PCB, which includes an AVR with the SPI interface, the pinout, as
shown in the gure below, should be used.
Figure 3-13. SPI Header Pinout
PDO/MISO
SCK
/RESET
VCC
PDI/MOSI
GND
1 2
SPI
Table 3-8. SPI Pin Mapping
AVR PORT Pins Target Pins SPI Pinout
Pin 1 (TCK) SCK 3
Pin 2 (GND) GND 6
Pin 3 (TDO) MISO 1
Pin 4 (VTG) VTG 2
Pin 5 (TMS)
Pin 6 (nSRST) /RESET 5
Pin 7 (not connected)
Pin 8 (nTRST)
Pin 9 (TDI) MOSI 4