Implemented TMC2209 Register Read/Write

motor-control/firmware/src/tmc2209/uart_interface.cpp

@@ -0,0 +1,80 @@
+#include "pico/stdlib.h"
+#include "pico.h"
+#include "hardware/uart.h"
+
+#include "tmc2209.hpp"
+
+TMC2209_UART::TMC2209_UART(
+    uart_inst_t *uart_inst, 
+    uint8_t node_address, 
+    uint baudrate, 
+    uint tx_pin, 
+    uint rx_pin
+) {
+    this->uart_inst = uart_inst;
+    this->node_address = node_address & 0b11;
+    this->baudrate = baudrate;
+    this->tx_pin = tx_pin;
+    this->rx_pin = rx_pin;
+}
+
+void TMC2209_UART::init() {
+    gpio_set_function(this->tx_pin, UART_FUNCSEL_NUM(this->uart_inst, this->tx_pin));
+    gpio_set_function(this->rx_pin, UART_FUNCSEL_NUM(this->uart_inst, this->rx_pin));
+    
+    // UART format: 8 data bits, 1 stop bit, no parity
+    // -> https://www.analog.com/media/en/technical-documentation/data-sheets/TMC2209_datasheet_rev1.09.pdf
+    uart_set_format(this->uart_inst, 8, 1, UART_PARITY_NONE);
+
+    // Clear to Send (CTS) and Request to Send (RTS) are not used
+    // (This is for automaticlly telling the other side that it is ready to receive/send data)
+    uart_set_hw_flow(this->uart_inst, false, false);
+
+    uart_set_fifo_enabled(this->uart_inst, true);
+
+    uart_init(this->uart_inst, this->baudrate);
+}
+
+uint8_t TMC2209_UART::calc_crc8_atm(uint8_t *data, uint8_t size) {
+    int i,j;
+    uint8_t crc = 0; // CRC located in last byte of message
+    uint8_t currentByte;
+
+    for (i=0; i<size; i++) {    // Execute for all bytes of a message
+        currentByte = data[i];  // Retrieve a byte to be sent from Array
+
+        for (j=0; j<8; j++) {
+            if ((crc >> 7) ^ (currentByte & 0x01)) { // update CRC based result of XOR operation
+                crc = (crc << 1) ^ 0x07;
+            } else {
+                crc = (crc << 1);
+            }
+            currentByte = currentByte >> 1;
+        } // for CRC bit
+    } // for message byte
+
+    return crc;
+}
+
+uint32_t TMC2209_UART::read(uint8_t address) {
+    uint8_t data[4] = {
+        0b01010101, // Sync byte
+        this->node_address, // Node address
+        (address & (uint8_t)(0x7F)), // Register address, last bit is 0 for read
+        0
+    };
+
+    data[3] = this->calc_crc8_atm(data, 3);
+
+    uart_write_blocking(this->uart_inst, data, 4);
+
+    uint8_t response[12];
+    uart_read_blocking(this->uart_inst, response, 12);
+
+    if(response[11] != calc_crc8_atm(&response[4], 7)) {
+        this->crc_error_flag = true;
+        return 0;
+    } else {
+        return *((uint32_t*) &response[7]);
+    }
+}