serial_debugger/hardware/mux_rpi/README.md

# MUX - Raspberry Pi Edition

This folder contains the necessary sources and information to build a MUX for Raspberry Pis. This mux can be used independently or with the controller.

Note : The mux needs to be configured via sources if not used with the controller.

## Important Considerations

- The Raspberry Pi 4 has 5 available UARTS and we only document how to wire for UART0/1 and UART5
- The Raspberry Pi's prior to the 4 had only UART0 exposed. Please use ONLY the UART0 configuration and setup for these devices.

## Hardware / BoM

| Item | Quantity | Unit Cost |
| ---- | -------- | --------- |
| [Feather M0 Basic Proto](https://www.adafruit.com/product/2772) | 1 | $19.95 |
| [FeatherWing Proto](https://www.adafruit.com/product/2884) | 1 | $4.95 |
| [2x20 pin IDC Box Header](https://www.adafruit.com/product/1993) | 1 | $0.75 |
| [GPIO Ribbon Cable for Raspberry Pi](https://www.adafruit.com/product/1988) | 1 | $2.95 |
| [Header Kit for Feather](https://www.adafruit.com/product/2886) | 1 | $0.96 |
| [I2C Non-Volatile FRAM Breakout](https://www.adafruit.com/product/1895) | 2 | $9.95 |

## Schematic

This build is ```i2c``` focused for additional parts. Please hookup using standard ```i2c``` methods.

| Raspberry Pi Header Pin | Arduino Pin |
| ----------------------- | ----------- |
| 6 | Gnd |
| 8 | A1 |
| 10 | A2 |
| 32 | 10 |
| 33 | 11 |
| 1 | NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER |
| 2 | NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER |
| 3 | NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER |
| 4 | NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER |
| 13 | NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER |
| 14 | NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER |
| 15 | NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER |
| 16 | NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER |

## Libraries Used

### Local

These libraries are used by the project and contained in the ```src/``` folder local to the project.

### External

These libraries are used by the project and can be installed via the Arduino IDE library manager.

- [CircularBuffer](https://github.com/rlogiacco/CircularBuffer)

## Implementation (Incomplete)

- FRAM break out for configuration persistence
- Fall back to saved config *and* goes into stand alone via usb port *if* it's not seeing the main board
- Receive configuration over i2c
- Save configuration to FRAM
- FRAM config reading
- Ability to have USB *and* i2c for the UART output
  - Use ring buffer @ 16k for i2c
  - Send direct to USB and then add to ring buffer (always send over usb even if not used)

## Implementation (Complete)

## Building / Uploading

The ```make.ps1```, ```build.ps1``` and ```upload.ps1``` scripts can be used to build/upload this project. These scripts call the ```arduino-cli``` commands programatically.
Overhaul source layout to facilitate MUXes being added 2020-09-09 23:36:39 +00:00			`# MUX - Raspberry Pi Edition`

			`This folder contains the necessary sources and information to build a MUX for Raspberry Pis. This mux can be used independently or with the controller.`

			`Note : The mux needs to be configured via sources if not used with the controller.`

			`## Important Considerations`

			`- The Raspberry Pi 4 has 5 available UARTS and we only document how to wire for UART0/1 and UART5`
			`- The Raspberry Pi's prior to the 4 had only UART0 exposed. Please use ONLY the UART0 configuration and setup for these devices.`

			`## Hardware / BoM`

			`\| Item \| Quantity \| Unit Cost \|`
			`\| ---- \| -------- \| --------- \|`
			`\| [Feather M0 Basic Proto](https://www.adafruit.com/product/2772) \| 1 \| $19.95 \|`
			`\| [FeatherWing Proto](https://www.adafruit.com/product/2884) \| 1 \| $4.95 \|`
			`\| [2x20 pin IDC Box Header](https://www.adafruit.com/product/1993) \| 1 \| $0.75 \|`
			`\| [GPIO Ribbon Cable for Raspberry Pi](https://www.adafruit.com/product/1988) \| 1 \| $2.95 \|`
			`\| [Header Kit for Feather](https://www.adafruit.com/product/2886) \| 1 \| $0.96 \|`
			`\| [I2C Non-Volatile FRAM Breakout](https://www.adafruit.com/product/1895) \| 2 \| $9.95 \|`

Start implmenetation of rpi mux 2020-09-11 02:28:31 +00:00			`## Schematic`

			This build is ```i2c``` focused for additional parts. Please hookup using standard ```i2c``` methods.

			`\| Raspberry Pi Header Pin \| Arduino Pin \|`
			`\| ----------------------- \| ----------- \|`
			`\| 6 \| Gnd \|`
			`\| 8 \| A1 \|`
			`\| 10 \| A2 \|`
			`\| 32 \| 10 \|`
			`\| 33 \| 11 \|`
			`\| 1 \| NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER \|`
			`\| 2 \| NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER \|`
			`\| 3 \| NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER \|`
			`\| 4 \| NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER \|`
			`\| 13 \| NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER \|`
			`\| 14 \| NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER \|`
			`\| 15 \| NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER \|`
			`\| 16 \| NOT CONNECTED TO ANYTHING / CUT PIN ON HEADER \|`

			`## Libraries Used`

			`### Local`

			These libraries are used by the project and contained in the ```src/``` folder local to the project.

			`### External`

			`These libraries are used by the project and can be installed via the Arduino IDE library manager.`

			`- [CircularBuffer](https://github.com/rlogiacco/CircularBuffer)`

Overhaul source layout to facilitate MUXes being added 2020-09-09 23:36:39 +00:00			`## Implementation (Incomplete)`

			`- FRAM break out for configuration persistence`
			`- Fall back to saved config and goes into stand alone via usb port if it's not seeing the main board`
			`- Receive configuration over i2c`
			`- Save configuration to FRAM`
			`- FRAM config reading`
			`- Ability to have USB and i2c for the UART output`
			`- Use ring buffer @ 16k for i2c`
			`- Send direct to USB and then add to ring buffer (always send over usb even if not used)`

			`## Implementation (Complete)`

			`## Building / Uploading`

			The ```make.ps1```, ```build.ps1``` and ```upload.ps1``` scripts can be used to build/upload this project. These scripts call the ```arduino-cli``` commands programatically.