Homie is an attempt to create wired smart-home devices. Those devices are connected using DOSE.
Every device has two 4P4C jacks. This enables daisy-chaining the devices into one serial bus. The first and last device have to be terminated using a 120Ω resistor.
The bus interface:
| Pin | Description |
|---|---|
| 1 | GND |
| 2 | CAN LOW |
| 3 | CAN HIGH |
| 4 | +5V |
The debug interface features:
- Accessing board RESET and BOOT selector line
- Debug UART
- SWD Interface
- Power supply
The pin layout is designed to tolerate wrongly-connected pin header.
All data lines (SWDIO, SWCLK, RX, TX) hat to be protected against short-circuit on the debug port. (E.g. series resistors, ...)
| Description | Name | Pin | Pin | Name | Description |
|---|---|---|---|---|---|
| Selectes the boot mode. Pulled with a on-board resistor to the right level. | BOOT | 1 | 2 | RX | Debug UART RX (Debug Adapter -> Board) |
| Voltage for all IO pins | VIO | 3 | 4 | TX | Debug UART TX (Board -> Debug Adapter) |
| NC | 5 | 6 | VIN | Supply for the borad. The debug adapter has to protect this current direct using a diode. | |
| SWD data line | SWDIO | 7 | 8 | SWCLK | SWD clock line |
| Board reset. Low active. | RESET | 9 | 10 | GND | Ground |