Add additional serial ports via SERCOM ; the mux_rpi build now has uart0/1, uart5 and a generic ttl pinout in case others are needed

hardware/mux_rpi/.gitignore

@@ -1 +1 @@
-build/
+./build/

hardware/mux_rpi/README.md

@@ -27,10 +27,10 @@ This build is ```i2c``` focused for additional parts. Please hookup using standa
 | Raspberry Pi Header Pin | Arduino Pin |
 | ----------------------- | ----------- |
 | 6 | Gnd |
-| 8 | A1 |
-| 10 | A2 |
-| 32 | 10 |
-| 33 | 11 |
+| 8 (TX) | D11 (RX) |
+| 10 (RX) | D10 (TX) |
+| 32 (TX) | MISO (RX) |
+| 33 (RX) | MOSI (TX) |
 | 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 |

hardware/mux_rpi/build.ps1

@@ -1 +1 @@
-arduino-cli compile --log-level=warn --fqbn adafruit:samd:adafruit_feather_m0 _controller.ino
+arduino-cli compile --log-level=warn --fqbn adafruit:samd:adafruit_feather_m0 mux_rpi.ino

hardware/mux_rpi/mux_rpi.ino

@@ -9,8 +9,10 @@
 #include <CircularBuffer.h>
 
 // Buffer for serial data -> i2c
-#define UART_BUFFER_SIZE 16 * 1024
-CircularBuffer<char,UART_BUFFER_SIZE> uartBuffer;
+CircularBuffer<byte, 16 * 1024> uartBufferOutbound;
+
+// Buffer for serial data <- i2c
+CircularBuffer<byte, 1024> uartBufferInbound;
 
 // Board LED Pin
 #define PIN_BOARD_LED 13
@@ -23,17 +25,19 @@ void timerConfigure(int sampleRate);
 
 // Additional serial ports for communication <> RPI
 //     https://learn.adafruit.com/using-atsamd21-sercom-to-add-more-spi-i2c-serial-ports?view=all#creating-a-new-serial
-//     RX -- A2 -- S 4:1
-//     TX -- A1 -- S 4:0
-//     RX -- 10 -- S 3:2
-//     TX -- 11 -- S 3:0
-Uart rpiUART0 (&sercom4, A1, A2, SERCOM_RX_PAD_1, UART_TX_PAD_0);
-Uart rpiUART5 (&sercom3, 10, 11, SERCOM_RX_PAD_2, UART_TX_PAD_0);
+//     D11 (RX) -- GPIO 8 (TX)
+//     D10 (TX) -- GPIO 10 (RX)
+//     MISO (RX) -- GPIO 32 (TX)
+//     MOSI (TX) -- GPIO 33 (RX)
 
-void SERCOM4_Handler() {
+Uart rpiUART0 (&sercom1, 10, 11, SERCOM_RX_PAD_0, UART_TX_PAD_2);
+Uart rpiUART5 (&sercom4, PIN_SPI_MISO, PIN_SPI_MOSI, SERCOM_RX_PAD_0, UART_TX_PAD_2);
+
+void SERCOM1_Handler() {
   rpiUART0.IrqHandler();
 }
-void SERCOM3_Handler() {
+
+void SERCOM4_Handler() {
   rpiUART5.IrqHandler();
 }
 
@@ -46,24 +50,38 @@ void setup() {
   timerConfigure(TIMER_MILLIS);
   timerStartCounter();
 
-  // Assign SERCOM functionality
-  pinPeripheral(A1, PIO_SERCOM);
-  pinPeripheral(A2, PIO_SERCOM);
-  pinPeripheral(10, PIO_SERCOM);
-  pinPeripheral(11, PIO_SERCOM);
-
   // Setup serial ports
   Serial.begin(115200);
+  Serial1.begin(115200);
   rpiUART0.begin(115200);
   rpiUART5.begin(115200);
+
+  // Assign SERCOM functionality
+  pinPeripheral(10, PIO_SERCOM);
+  pinPeripheral(11, PIO_SERCOM);
 }
 
 // Main function
+int serialIncomingByte;
 void loop() {
-  digitalWrite(PIN_BOARD_LED, HIGH);
-  delay(500);
-  digitalWrite(PIN_BOARD_LED, LOW);
-  delay(500);
+  while (Serial.available()) {
+    uartBufferOutbound.push(Serial.read());
+    Serial1.write(uartBufferOutbound.last());
+    rpiUART0.write(uartBufferOutbound.last());
+    rpiUART5.write(uartBufferOutbound.last());
+  }
+  while (Serial1.available()) {
+    uartBufferInbound.push(Serial1.read());
+    Serial.write(uartBufferInbound.last());
+  }
+  while (rpiUART0.available()) {
+    uartBufferInbound.push(rpiUART0.read());
+    Serial.write(uartBufferInbound.last());
+  }
+  while (rpiUART5.available()) {
+    uartBufferInbound.push(rpiUART5.read());
+    Serial.write(uartBufferInbound.last());
+  }
 }
 
 // Timer handler