usbcomm.c

/* ===================================================================== *
 *                             UART HANDLING                             *
 * ===================================================================== */
 
#include "usbcomm.h"
 
extern MessageBufferHandle_t xUsbTxBuff;
extern MessageBufferHandle_t xUsbRxBuff;
 
uint8_t usbRxBuff[USB_RX_SIZE];
uint8_t usbRxBuffIdx = 0;
 
/* =============================================================================== */
void vUsbTransmit(void *argument) {
  const TickType_t timeout = portMAX_DELAY;
  uint8_t rxData[100];
 
  UART *usb = DeviceHandle_getHandle("USB").device;
 
  for (;;) {
    // Read byte from UART Tx buffer, skip loop if empty
    if (!xMessageBufferReceive(xUsbTxBuff, (void *)rxData, 100, timeout))
      continue;
 
    usb->print(usb, (char *)rxData);
  }
}
 
/* =============================================================================== */
void vUsbReceive(void *argument) {
  const TickType_t timeout = portMAX_DELAY;
  uint8_t rxData;
 
  UART *usb    = DeviceHandle_getHandle("USB").device;
  Shell *shell = argument;
 
  for (;;) {
    // Read byte from UART Rx buffer, skip loop if empty
    if (!xStreamBufferReceive(xUsbRxBuff, (void *)&rxData, 1, timeout))
      continue;
 
    // Send byte back for display
    usb->send(usb, rxData);
 
    // Process command and reset buffer on <Enter> input
    if (rxData == CARRIAGE_RETURN) {
      usb->print(usb, "\n");              // Send newline back for display
      usbRxBuff[usbRxBuffIdx - 1] = '\0'; // Replace carriage return with null terminator
      shell->runTask(shell, usbRxBuff);   // Run shell program as task
      usbRxBuffIdx = 0;                   // Reset buffer
    }
 
    // Clear terminal on <Ctrl-c> input
    else if (rxData == SIGINT) {
      shell->clear(shell);
      usbRxBuffIdx = 0;
    }
 
    // Erase character and move cursor backwards on <BS> input
    else if (rxData == BACKSPACE) {
      usb->print(usb, " \b");
      if (usbRxBuffIdx)
        usbRxBuffIdx -= 2;
    }
  }
}
 
/* =============================================================================== */
void USART6_IRQHandler() {
  BaseType_t xHigherPriorityTaskWoken = pdFALSE;
 
  // Read in data from USART6
  while ((USART6->SR & USART_SR_RXNE) == 0);
  uint8_t rxData            = USART6->DR & 0xFF;
 
  usbRxBuff[usbRxBuffIdx++] = rxData;
  usbRxBuffIdx %= USB_RX_SIZE;
 
  xStreamBufferSendFromISR(xUsbRxBuff, (void *)&rxData, 1, &xHigherPriorityTaskWoken);
  portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
}