External programming adapters often utilize dedicated interfaces and associated protocols which permit programming and debugging of the target device. Protocols with which one can program an MCU include the following:
|
Name |
Pins |
Features |
Description |
|
SPI (ISP) |
4 |
program |
Serial Peripheral Interface (SPI), used with older AVR MCUs to access its Serial Programmer mode (In-circuit Serial Programming (ISP)). |
|
JTAG |
5 |
program debug boundary |
Dedicated, industry-standard on-chip interface for programming and debugging support. Supported on AVR ATxmega devices. |
|
UPDI |
1 |
program debug |
The Unified Programming and Debug Interface (UDPI) used with newer AVR MCUs, including ATtiny ... |
