atmega8a_rgb-night-light/firmware/src/usart.c

#include "usart.h"

void (*EOT_Handler)(volatile char *rx_buffer) = NULL;

volatile char rx_buffer[RX_BUFFER_SIZE];
volatile uint8_t rx_buffer_idx = 0;
volatile bool rx_received_packet = false;

ISR(USART_RXC_vect) {
  char c = UDR;

  if (rx_buffer_idx >= RX_BUFFER_SIZE - 1) rx_buffer_idx = 0;

  rx_buffer[rx_buffer_idx++] = c;

  if (c == EOT || c == '\r' || c == '\n') {
    rx_buffer[rx_buffer_idx] = '\0';
    rx_buffer_idx = 0;
    if (EOT_Handler != NULL) (*EOT_Handler)(rx_buffer);
  }
}

void USART_SetReceiveHandler(void (*handler)(volatile char *rx_buffer)) {
  EOT_Handler = handler;
}

void USART_OnReceivePacketHandler(void) {
  if (EOT_Handler != NULL && rx_received_packet) {
    (*EOT_Handler)(rx_buffer);
    rx_received_packet = false;
  }
}

void USART_Init(void) {
  /**
   * USART
   * 8-bit char size, 1 stop bit, even parity, baud 9600
   */
  DDRD &= ~_BV(PD0);
  DDRD |= _BV(PD1);
  UCSRB |= _BV(RXEN) | _BV(TXEN) | _BV(RXCIE);
  UCSRC = _BV(URSEL) | _BV(UCSZ0) | _BV(UCSZ1) | _BV(UPM1);
  UBRRH = UBRRH_VALUE;
  UBRRL = UBRRL_VALUE;
}

void USART_SendChar(char c) {
  loop_until_bit_is_set(UCSRA, UDRE);
  UDR = c;
}

void USART_SendStr(char *str) {
  char c;

  while ((c = *str++) != '\0') {
    USART_SendChar(c);
  }
}

void USART_SendInt16(int16_t num) {
  char str[7];
  itoa(num, str, 10);
  USART_SendStr(str);
}