uart0.c

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/*
 * Copyright (c) 2020, Toshiba BRIL
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holder nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/**
 * \addtogroup nrf52840-dev Device drivers
 * @{
 *
 * \addtogroup nrf52840-uart UART driver
 * @{
 *
 * \file
 *         A header file for Contiki compatible UART driver.
 */
#include "contiki.h"
#include "nrf.h"
#include "nrf_uart.h"
#include "nrf_gpio.h"
#include "dev/uart0.h"
 
#include <stdlib.h>
#include <stdint.h>
/*---------------------------------------------------------------------------*/
static int (*input_handler)(unsigned char c);
 
#define UART_INSTANCE NRF_UART0
/*---------------------------------------------------------------------------*/
#define TX_PIN  NRF_UART0_TX_PIN
#define RX_PIN  NRF_UART0_RX_PIN
/*---------------------------------------------------------------------------*/
void
uart0_set_input(int (*input)(unsigned char c))
{
  input_handler = input;
 
  if(input != NULL) {
    nrf_uart_int_enable(UART_INSTANCE, NRF_UART_INT_MASK_RXDRDY);
    NVIC_ClearPendingIRQ(UARTE0_UART0_IRQn);
    NVIC_EnableIRQ(UARTE0_UART0_IRQn);
    nrf_uart_task_trigger(UART_INSTANCE, NRF_UART_TASK_STARTRX);
  } else {
    nrf_uart_int_disable(UART_INSTANCE, NRF_UART_INT_MASK_RXDRDY);
    NVIC_ClearPendingIRQ(UARTE0_UART0_IRQn);
    NVIC_DisableIRQ(UARTE0_UART0_IRQn);
    nrf_uart_task_trigger(UART_INSTANCE, NRF_UART_TASK_STOPRX);
  }
}
/*---------------------------------------------------------------------------*/
void
uart0_writeb(unsigned char c)
{
  nrf_uart_txd_set(UART_INSTANCE, c);
 
  /* Block if previous TX is ongoing */
  while(nrf_uart_event_check(UART_INSTANCE, NRF_UART_EVENT_TXDRDY) == false);
  nrf_uart_event_clear(UART_INSTANCE, NRF_UART_EVENT_TXDRDY);
}
/*---------------------------------------------------------------------------*/
void
uart0_init(unsigned long ubr)
{
  nrf_uart_disable(UART_INSTANCE);
  nrf_gpio_cfg_output(TX_PIN);
  nrf_gpio_pin_set(TX_PIN);
  nrf_gpio_cfg_input(RX_PIN, NRF_GPIO_PIN_NOPULL);
 
  nrf_uart_baudrate_set(UART_INSTANCE, UART0_CONF_BAUD_RATE);
  nrf_uart_configure(UART_INSTANCE, NRF_UART_PARITY_EXCLUDED,
                     NRF_UART_HWFC_DISABLED);
  nrf_uart_txrx_pins_set(UART_INSTANCE, TX_PIN, RX_PIN);
  nrf_uart_event_clear(UART_INSTANCE, NRF_UART_EVENT_TXDRDY);
  nrf_uart_enable(UART_INSTANCE);
  nrf_uart_task_trigger(UART_INSTANCE, NRF_UART_TASK_STARTTX);
}
/*---------------------------------------------------------------------------*/
void
UARTE0_UART0_IRQHandler(void)
{
  nrf_uart_event_clear(UART_INSTANCE, NRF_UART_EVENT_RXDRDY);
  input_handler(nrf_uart_rxd_get(UART_INSTANCE));
}
/*---------------------------------------------------------------------------*/
/**
 * @}
 * @}
 */