## Serial port functions and scenarios

### Serial port scenarios

```
0   UNUSED
1   MSP, CLI, TELEMETRY, GPS-PASTHROUGH
2   GPS ONLY
3   RX SERIAL ONLY
4   TELEMETRY ONLY
5   MSP, CLI, GPS-PASTHROUGH
6   CLI ONLY
7   GPS-PASSTHROUGH ONLY
8   MSP ONLY
```

### Contraints

* There must always be a port available to use for MSP
* There must always be a port available to use for CLI
* To use a port for a function, the function's corresponding feature must be enabled first.
e.g. to use GPS enable the GPS feature.
* If the configuration is invalid the serial port configuration will reset to it's defaults and features may be disabled.

### Examples

All examples assume default configuration (via cli `defaults` command)

a) GPS and FrSky TELEMETRY (when armed)

- TELEMETRY,MSP,CLI,GPS PASSTHROUGH on UART1
- GPS on UART2

```
feature TELEMETRY
feature GPS
save
```

b) RX SERIAL and FrSky TELEMETRY (when armed)

- TELEMETRY,MSP,CLI,GPS PASSTHROUGH on UART1
- RX SERIAL on UART2

```
feature -RX_PARALLEL_PWM
feature RX_SERIAL
feature TELEMETRY
set serial_port_2_scenario = 3
save
```

b) RX SERIAL and FrSky TELEMETRY via softserial

- MSP,CLI,GPS PASSTHROUGH on UART1
- RX SERIAL on UART2
- TELEMETRY on SOFTSERIAL1

```
feature -RX_PARALLEL_PWM
feature RX_SERIAL
feature TELEMETRY
feature SOFTSERIAL
set serial_port_2_scenario = 3
set serial_port_3_scenario = 4
save
```

c) GPS and FrSky TELEMETRY via softserial

- MSP,CLI,GPS PASSTHROUGH on UART1
- GPS on UART2
- TELEMETRY on SOFTSERIAL1

```
feature -RX_PARALLEL_PWM
feature RX_PPM
feature TELEMETRY
feature GPS
feature SOFTSERIAL
set serial_port_3_scenario = 4
save
```
d) RX SERIAL, GPS and TELEMETRY (when armed) MSP/CLI via softserial

- GPS on UART1
- RX SERIAL on UART2
- TELEMETRY,MSP,CLI,GPS PASSTHROUGH on SOFTSERIAL1

```
feature -RX_PARALLEL_PWM
feature TELEMETRY
feature GPS
feature RX_SERIAL
feature SOFTSERIAL
set serial_port_1_scenario = 2
set serial_port_2_scenario = 3
set serial_port_3_scenario = 1
set msp_baudrate = 19200
set cli_baudrate = 19200
set gps_passthrough_baudrate = 19200
save
```

e) HoTT Telemetry via UART2

- MSP,CLI,GPS PASSTHROUGH on UART1
- HoTT telemetry on UART2

```
feature -RX_PARALLEL_PWM
feature RX_PPM
feature TELEMETRY
set serial_port_2_scenario = 4
set telemetry_provider = 1
```

f) GPS, HoTT Telemetry via SoftSerial 1

- MSP,CLI,GPS PASSTHROUGH on UART1
- GPS on UART2
- HoTT telemetry on SOFTSERIAL1

```
feature -RX_PARALLEL_PWM
feature RX_PPM
feature TELEMETRY
feature GPS
feature SOFTSERIAL
set serial_port_3_scenario = 4
set telemetry_provider = 1
save
```

## CLI command differences from baseflight

### gps_baudrate
reason: simplify

Cleanflight uses normal baud rate values for gps baudrate, baseflight uses an index.

If an unsupported baud rate value is used the gps code will select 115200 baud.

example: `set gps_baudrate = 115200`


### gps_type
reason: renamed to `gps_provider` for consistency

### serialrx_type
reason: renamed to `serialrx_provider` for consistency

### rssi_aux_channel
reason: improved functionality

Cleanflight supports using any RX channel for rssi.  Baseflight only supports AUX1 to 4.

In Cleanflight a value of 0 disables the feature, a higher value indicates the channel number to read RSSI information from.

Example: to use RSSI on AUX1 in Cleanflight use `set rssi_aux_channel = 5`, since 5 is the first AUX channel.

### failsafe_detect_threshold
reason: improved functionality

See `failsafe_min_usec` and `failsafe_max_usec` in Failsafe documentation.