/*
 * Author: username
 * Date: 2024
 * filename: usart.c
 * description: module_purpose
 */

#ifndef __AVR_ATtiny404__
#define __AVR_ATtiny404__
#endif

#include "usart.h"
#include <avr/io.h>
#include <string.h>

// These are technically correct, but the libc requires F_CPU for delay stuff
// that doesn't match the actual F_CPU because it uses the value after the
// clock is divided.

// #define F_CPU 3333333UL
// #define F_PER F_CPU / 6

#define F_PER 3333333UL
#define USART0_BAUD_RATE(BAUD_RATE)                                            \
  ((float)(F_PER * 64 / (16 * (float)BAUD_RATE)) + 0.5)

// RX PIN6, TX PIN7
// ALT: RX PIN12 TX PIN11
void USART0_Init(void) {
  // Config TxD as output, and rx as input?
  PORTB.DIR &= ~(1 << 3);
  PORTB.DIR |= (1 << 2);

  // It says to set the TX pin high?
  // PORTB.OUT |= (1<<2);

  // set buad rate.
  USART0.BAUD = (uint16_t)USART0_BAUD_RATE(9600);
  // USART0.BAUD = 1388;

  // set the frame format.
  USART0.CTRLC = 0x3; // setting 8-bit mode.

  // Enable transmitter and receiver (USARTn.CTRLB)
  // USART0.CTRLB |= (1<<7)|(1<<6);
  USART0.CTRLB |= USART_TXEN_bm;
}

void USART0_Alt_Init(void) {
  // setup Alternate pints on PA1 and PA2
  PORTMUX.CTRLB |= PORTMUX_USART0_ALTERNATE_gc;
  PORTA.DIR |= (1 << 1);
  PORTA.DIR &= ~(1 << 2);

  // It says to set the TX pin high?
  // PORTA.OUT |= (1<<11);

  // set buad rate.
  USART0.BAUD = (uint16_t)USART0_BAUD_RATE(9600);

  // set the frame format.
  USART0.CTRLC = 0x3; // setting 8-bit mode.

  // Enable transmitter and receiver (USARTn.CTRLB)
  // USART0.CTRLB |= (1<<7)|(1<<6);
  USART0.CTRLB |= USART_TXEN_bm;
}

void USART0_sendChar(char c) {
  while (!(USART0.STATUS & USART_DREIF_bm)) {
    ;
  }
  USART0.TXDATAL = c;
  USART0.TXDATAH = c;
}

void USART0_sendString(char *str) {
  for (size_t i = 0; i < strlen(str); i++) {
    USART0_sendChar(str[i]);
  }
}