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serial_debugger/hardware/mux_rpi/mux_rpi.ino

140 lines
4.4 KiB
C++

// References / Resources / Inspiration
// https://gist.github.com/nonsintetic/ad13e70f164801325f5f552f84306d6f
// Varous system includes
#include <Arduino.h>
#include "wiring_private.h"
// Various library includes
#include <CircularBuffer.h>
// Buffer for serial data -> i2c
#define UART_BUFFER_SIZE 16 * 1024
CircularBuffer<char,UART_BUFFER_SIZE> uartBuffer;
// Board LED Pin
#define PIN_BOARD_LED 13
// Blinking timer setup
#define TIMER_MILLIS 500
bool ledState = false;
void TC5_Handler(void);
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);
void SERCOM4_Handler() {
rpiUART0.IrqHandler();
}
void SERCOM3_Handler() {
rpiUART5.IrqHandler();
}
// Setup stuff needed for build
void setup() {
// Setup board LED
pinMode(PIN_BOARD_LED, OUTPUT);
// Timer 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);
rpiUART0.begin(115200);
rpiUART5.begin(115200);
}
// Main function
void loop() {
digitalWrite(PIN_BOARD_LED, HIGH);
delay(500);
digitalWrite(PIN_BOARD_LED, LOW);
delay(500);
}
// Timer handler
void TC5_Handler (void) {
if(ledState == true) {
digitalWrite(PIN_BOARD_LED, HIGH);
} else {
digitalWrite(PIN_BOARD_LED, LOW);
}
ledState = !ledState;
TC5->COUNT16.INTFLAG.bit.MC0 = 1; //Writing a 1 to INTFLAG.bit.MC0 clears the interrupt so that it will run again
}
//Configures the TC to generate output events at the sample frequency.
//Configures the TC in Frequency Generation mode, with an event output once
//each time the audio sample frequency period expires.
void timerConfigure(int sampleRate) {
// select the generic clock generator used as source to the generic clock multiplexer
GCLK->CLKCTRL.reg = (uint16_t) (GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID(GCM_TC4_TC5)) ;
while (GCLK->STATUS.bit.SYNCBUSY);
timerReset(); //reset TC5
// Set Timer counter 5 Mode to 16 bits, it will become a 16bit counter ('mode1' in the datasheet)
TC5->COUNT16.CTRLA.reg |= TC_CTRLA_MODE_COUNT16;
// Set TC5 waveform generation mode to 'match frequency'
TC5->COUNT16.CTRLA.reg |= TC_CTRLA_WAVEGEN_MFRQ;
//set prescaler
//the clock normally counts at the GCLK_TC frequency, but we can set it to divide that frequency to slow it down
//you can use different prescaler divisons here like TC_CTRLA_PRESCALER_DIV1 to get a different range
TC5->COUNT16.CTRLA.reg |= TC_CTRLA_PRESCALER_DIV1024 | TC_CTRLA_ENABLE; //it will divide GCLK_TC frequency by 1024
//set the compare-capture register.
//The counter will count up to this value (it's a 16bit counter so we use uint16_t)
//this is how we fine-tune the frequency, make it count to a lower or higher value
//system clock should be 1MHz (8MHz/8) at Reset by default
TC5->COUNT16.CC[0].reg = (uint16_t) (SystemCoreClock / sampleRate);
while (timerIsSyncing());
// Configure interrupt request
NVIC_DisableIRQ(TC5_IRQn);
NVIC_ClearPendingIRQ(TC5_IRQn);
NVIC_SetPriority(TC5_IRQn, 0);
NVIC_EnableIRQ(TC5_IRQn);
// Enable the TC5 interrupt request
TC5->COUNT16.INTENSET.bit.MC0 = 1;
while (timerIsSyncing()); //wait until TC5 is done syncing
}
//Function that is used to check if TC5 is done syncing
//returns true when it is done syncing
bool timerIsSyncing() {
return TC5->COUNT16.STATUS.reg & TC_STATUS_SYNCBUSY;
}
//This function enables TC5 and waits for it to be ready
void timerStartCounter() {
TC5->COUNT16.CTRLA.reg |= TC_CTRLA_ENABLE; //set the CTRLA register
while (timerIsSyncing()); //wait until snyc'd
}
//Reset TC5
void timerReset() {
TC5->COUNT16.CTRLA.reg = TC_CTRLA_SWRST;
while (timerIsSyncing());
while (TC5->COUNT16.CTRLA.bit.SWRST);
}
//disable TC5
void timerDisable() {
TC5->COUNT16.CTRLA.reg &= ~TC_CTRLA_ENABLE;
while (timerIsSyncing());
}