A programmer with DTR and RTS outputs to allow programming without additional circuitry. It also supplies 3.3 V to the connected device. Hardware schematic and PCB can be found here.
Pinout (pin 1 on front left side):
| Pin | Function |
|---|---|
| 1 | 3.3 V |
| 2 | GND |
| 3 | Reset (RTS) |
| 4 | Boot (DTR) |
| 5 | TX |
| 6 | RX |