fw/uart.c (22b4569) - mips_sys · BlinkenArea

uart.c

#include "uart.h"

static volatile unsigned char *const uart_ptr =
  (volatile unsigned char *)0x80000300;

/**
 * @brief configure baudrate scaler
 * @param[in] scale baudrate scaler (1 = 7.143 Mhz)
 */
void uart_cfg_scale(unsigned short scale)
{
  *(unsigned short *)(uart_ptr + 0) = scale;
}

/**
 * @brief configure number of data bits
 * @param[in] bits number of data bits
 */
void uart_cfg_bits(unsigned char bits)
{
  *(uart_ptr + 2) = bits;
}

/**
 * @brief configure number of stop bits
 * @param[in] stop number of stop bits
 */
void uart_cfg_stop(unsigned char stop)
{
  *(uart_ptr + 3) = stop;
}

/**
 * @brief check if transmitting a character is possible
 * @return if transmitting a character is possible
 */
int uart_can_tx(void)
{
  return *(uart_ptr + 4);
}

/**
 * @brief transmit a character
 * @param[in] chr character to transmit
 */
void uart_tx(unsigned short chr)
{
  while (!*(uart_ptr + 4));
  *(unsigned short *)(uart_ptr + 8) = chr;
}

/**
 * @brief check if receiving a character is possible
 * @return if receiving a character is possible
 */
int uart_can_rx(void)
{
  return *(uart_ptr + 5);
}

/**
 * @brief receive a character
 * @return character received
 */
unsigned short uart_rx(void)
{
  while (!*(uart_ptr + 5));
  unsigned short chr = *(unsigned short *)(uart_ptr + 12);
  return chr;
}

/**
 * @brief determine if character is an error character
 * @param[in] chr character to check
 * @return if error
 */
int uart_is_err(unsigned short chr)
{
  return chr >> 15;
}

mips_sys

add read_enable signal to data bus and some peripherals