The ATtiny817 supports UPDI (Unified Program and Debug Interface), which is a Microchip proprietary interface for external programming and on-chip debugging of a device.
Atmel-ICE supports the UPDI interface. The 2x3 connector for the interface is a 2.54mm pitch through-hole header.
Figure 1. UPDI Interface
| Signal Name | Pin Number in the Header | Pin Number in the MCU |
|---|---|---|
| PA0_UPDI_DATA | 1 | 23 |
| VCC | 2 | 4 |
| GND | 6 | 3 |