uart_driver.c

#include "uart_driver.h"
#include "uart.h"
#include "mac_packet.h"
#include "payload.h"
#include "ppool.h"
#include "utils.h"

volatile packet_union_t pkt_buf_0_;
volatile packet_union_t pkt_buf_1_;

volatile packet_union_t* in_pkt_;
volatile packet_union_t* last_bldc_packet;
volatile uint8_t last_bldc_packet_is_new;

volatile uint32_t in_pkt_idx_;
volatile uint32_t in_pkt_len_;
volatile uint8_t in_pkt_crc_;

const uint8_t crc8_table[] = {
0x00, 0xD5, 0x7F, 0xAA, 0xFE, 0x2B, 0x81, 0x54, 0x29, 0xFC, 0x56, 0x83, 0xD7, 0x02, 0xA8, 0x7D,
0x52, 0x87, 0x2D, 0xF8, 0xAC, 0x79, 0xD3, 0x06, 0x7B, 0xAE, 0x04, 0xD1, 0x85, 0x50, 0xFA, 0x2F,
0xA4, 0x71, 0xDB, 0x0E, 0x5A, 0x8F, 0x25, 0xF0, 0x8D, 0x58, 0xF2, 0x27, 0x73, 0xA6, 0x0C, 0xD9,
0xF6, 0x23, 0x89, 0x5C, 0x08, 0xDD, 0x77, 0xA2, 0xDF, 0x0A, 0xA0, 0x75, 0x21, 0xF4, 0x5E, 0x8B,
0x9D, 0x48, 0xE2, 0x37, 0x63, 0xB6, 0x1C, 0xC9, 0xB4, 0x61, 0xCB, 0x1E, 0x4A, 0x9F, 0x35, 0xE0,
0xCF, 0x1A, 0xB0, 0x65, 0x31, 0xE4, 0x4E, 0x9B, 0xE6, 0x33, 0x99, 0x4C, 0x18, 0xCD, 0x67, 0xB2,
0x39, 0xEC, 0x46, 0x93, 0xC7, 0x12, 0xB8, 0x6D, 0x10, 0xC5, 0x6F, 0xBA, 0xEE, 0x3B, 0x91, 0x44,
0x6B, 0xBE, 0x14, 0xC1, 0x95, 0x40, 0xEA, 0x3F, 0x42, 0x97, 0x3D, 0xE8, 0xBC, 0x69, 0xC3, 0x16,
0xEF, 0x3A, 0x90, 0x45, 0x11, 0xC4, 0x6E, 0xBB, 0xC6, 0x13, 0xB9, 0x6C, 0x38, 0xED, 0x47, 0x92,
0xBD, 0x68, 0xC2, 0x17, 0x43, 0x96, 0x3C, 0xE9, 0x94, 0x41, 0xEB, 0x3E, 0x6A, 0xBF, 0x15, 0xC0,
0x4B, 0x9E, 0x34, 0xE1, 0xB5, 0x60, 0xCA, 0x1F, 0x62, 0xB7, 0x1D, 0xC8, 0x9C, 0x49, 0xE3, 0x36,
0x19, 0xCC, 0x66, 0xB3, 0xE7, 0x32, 0x98, 0x4D, 0x30, 0xE5, 0x4F, 0x9A, 0xCE, 0x1B, 0xB1, 0x64,
0x72, 0xA7, 0x0D, 0xD8, 0x8C, 0x59, 0xF3, 0x26, 0x5B, 0x8E, 0x24, 0xF1, 0xA5, 0x70, 0xDA, 0x0F,
0x20, 0xF5, 0x5F, 0x8A, 0xDE, 0x0B, 0xA1, 0x74, 0x09, 0xDC, 0x76, 0xA3, 0xF7, 0x22, 0x88, 0x5D,
0xD6, 0x03, 0xA9, 0x7C, 0x28, 0xFD, 0x57, 0x82, 0xFF, 0x2A, 0x80, 0x55, 0x01, 0xD4, 0x7E, 0xAB,
0x84, 0x51, 0xFB, 0x2E, 0x7A, 0xAF, 0x05, 0xD0, 0xAD, 0x78, 0xD2, 0x07, 0x53, 0x86, 0x2C, 0xF9
};

uint8_t update_crc8( uint8_t crc, uint8_t c ) {
  return (crc8_table[crc ^ c]);
}

uint8_t calculate_crc8(uint8_t *p, unsigned int length) {
  uint8_t crc;
  unsigned int i;

  crc = 0;

  for (i=0; i < length; i++) {
    crc = update_crc8(crc,*p++);
  }
  return crc;
}

void uartInit() {
    /// UART2 for RS-232 w/PC @ 230400, 8bit, No parity, 1 stop bit
    unsigned int U2MODEvalue, U2STAvalue, U2BRGvalue;
    U2MODEvalue = UART_EN & UART_IDLE_CON & UART_IrDA_DISABLE &
                  UART_MODE_SIMPLEX & UART_UEN_00 & UART_DIS_WAKE &
                  UART_DIS_LOOPBACK & UART_DIS_ABAUD & UART_UXRX_IDLE_ONE &
                  UART_BRGH_FOUR & UART_NO_PAR_8BIT & UART_2STOPBITS;
    U2STAvalue  = UART_INT_RX_CHAR & UART_SYNC_BREAK_DISABLED &
                  UART_TX_ENABLE & UART_ADR_DETECT_DIS &
                  UART_IrDA_POL_INV_ZERO; // If not, whole output inverted.
    U2BRGvalue  = 10; // Approximately 830kBaud

    OpenUART2(U2MODEvalue, U2STAvalue, U2BRGvalue);

    in_pkt_ = &(pkt_buf_0_);
    last_bldc_packet = &(pkt_buf_1_);
    last_bldc_packet_is_new = 0;

    ConfigIntUART2(UART_RX_INT_EN & UART_RX_INT_PR6);
}

//General blocking UART send function, appends basic checksum
unsigned char uartSend(unsigned char length, unsigned char *frame) {
    int i,j;
    
    // Calculate CRC and store at end of packet
    frame[length-1] = calculate_crc8(frame,length-1);

    LED_3=!LED_3;
    
    //send payload data
    for (i = 0; i < length; i++) {
        while(BusyUART2());
        WriteUART2(frame[i]);
        for(j = 0; j < 200; j++); //Brief wait allows mbed to keep up
    }

    return 1;
}

void __attribute__((__interrupt__, no_auto_psv)) _U2RXInterrupt(void) {
    unsigned char c;

    while(U2STAbits.URXDA) {
      c = U2RXREG;
      // If we just received the second character, set packet length
      if (in_pkt_idx_ == 1) {
        in_pkt_len_ = c;
      }

      // If there has been a parse error, reset packet buffer
      if ((in_pkt_idx_ == 0 && c != PKT_START_CHAR) || in_pkt_len_ < sizeof(header_t)+1 ) {
        in_pkt_idx_ = 0;
        in_pkt_len_ = MAX_PACKET_LENGTH;
        in_pkt_crc_ = 0;

      // Store byte in packet buffer and update CRC
      } else {
        in_pkt_->raw[in_pkt_idx_++] = c;
        in_pkt_crc_ = update_crc8(in_pkt_crc_, c);
      }

      // If we just received the last character and CRC is good,
      // swap with last_packet and reset packet buffer
      if (in_pkt_idx_ == in_pkt_len_) {
        if (in_pkt_crc_ == 0) {
          last_bldc_packet_is_new = 1;
          LED_2 ^= 1;
          LED_3 = 1;
          if(last_bldc_packet == &(pkt_buf_0_)) {
              last_bldc_packet = &(pkt_buf_1_);
              in_pkt_ = &(pkt_buf_0_);
          } else {
              last_bldc_packet = &(pkt_buf_0_);
              in_pkt_ = &(pkt_buf_1_);
          }
        }
        in_pkt_idx_ = 0;
        in_pkt_len_ = MAX_PACKET_LENGTH;
        in_pkt_crc_ = 0;
      }
    }

    if(U2STAbits.OERR) {
        U2STAbits.OERR = 0;
    }
    
    _U2RXIF = 0;
}