Pins other than USB/serial may be varied
| Pin | Signal | Description |
| 21,22 | Vbat | Charge in |
| 16 | Vbus | USB +5V |
| 15 | USB D+ | |
| 14 | Tx | serial |
| 13 | Rx | serial |
| 12 | PWR GND | |
| 10 | USB D- | |
| 9 | FF TxD | |
| 8 | FF RxD | |
| 6 | Auto PWR | |
|
1,2,3,4,5,7,11,17, 18,19,20,23,24 |
GND |
R=1k required in serial cable?

