gpsacquisition.c

/* ===================================================================== *
 *                                   GPS                                 *
 * ===================================================================== */
 
#include "gpsacquisition.h"
 
#include "packets.h"
 
extern MessageBufferHandle_t xLoRaTxBuff;
extern MessageBufferHandle_t xUsbTxBuff;
extern StreamBufferHandle_t xGpsRxBuff;
extern SemaphoreHandle_t xUsbMutex;
 
uint8_t gpsRxBuff[GPS_RX_SIZE];
uint8_t gpsRxBuffIdx = 0;
 
void vGpsTransmit(void *argument) {
  const TickType_t xFrequency = pdMS_TO_TICKS(500);
  const TickType_t blockTime  = pdMS_TO_TICKS(250);
  char gpsString[100];
 
  SAM_M10Q_t *gps         = DeviceList_getDeviceHandle(DEVICE_GPS).device;
  UART_t *usb             = DeviceList_getDeviceHandle(DEVICE_UART_USB).device;
  enum State *flightState = StateHandle_getHandle("FlightState").state;
 
  for (;;) {
    // Block until 500ms interval
    TickType_t xLastWakeTime = xTaskGetTickCount();
    vTaskDelayUntil(&xLastWakeTime, xFrequency);
 
    // Send GPS poll message
    gps->base.print(&gps->base, GPS_PUBX_POLL);
 
    // Read string from UART Rx buffer, skip loop if empty
    if (!xStreamBufferReceive(xGpsRxBuff, (void *)&gpsString, gpsRxBuffIdx, blockTime))
      continue;
 
    struct GPS_Data gpsData;
    gps->decode(gps, gpsString, &gpsData);
    usb->print(usb, gpsString);
    gpsRxBuffIdx = 0;
 
    #ifdef DEBUG
      if ((xSemaphoreTake(xUsbMutex, pdMS_TO_TICKS(0))) == pdTRUE) {
        char debugStr[100];
        snprintf(debugStr, 100, "[GPS] %d:%d:%d\n\r", gpsData.hour, gpsData.minute, gpsData.second);
        xMessageBufferSend(xUsbTxBuff, (void *)debugStr, 100, 0);
        xSemaphoreGive(xUsbMutex);
      }
    #endif
 
    SX1272_Packet gpsPacket = SX1272_GPSData(
        LORA_HEADER_GPS_DATA,
        gpsData.latitude,
        gpsData.longitude,
        (*flightState << 4) | gpsData.lock
    );
    // Add packet to queue
    // TODO: this needs to be refactored to not use the same buffer, or
    //       alternatively (probably better) refactor LoRa task to use
    //       a queue instead of a buffer to allow multiple writers.
    xMessageBufferSend(xLoRaTxBuff, &gpsPacket, LORA_MSG_LENGTH, blockTime);
  }
}
 
/* =============================================================================== */
void USART3_IRQHandler() {
  BaseType_t xHigherPriorityTaskWoken = pdFALSE;
 
  // Read in data from USART3
  while ((USART3->SR & USART_SR_RXNE) == 0);
  uint8_t rxData = USART3->DR & 0xFF;
 
  //
  gpsRxBuff[gpsRxBuffIdx++]  = rxData;
  gpsRxBuffIdx              %= GPS_RX_SIZE;
 
  // Send message to buffer on carriage return
  if (rxData == LINE_FEED) {
    xStreamBufferSendFromISR(xGpsRxBuff, (void *)gpsRxBuff, gpsRxBuffIdx, &xHigherPriorityTaskWoken);
    portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
  }
}