【国民技术N32项目移植】N32WB452芯片移植--2、串口输出重定向

准备工作

查看SDK原有的log.c源码

打开官方提供的 Nationstech.N32WB452_Library.2.0.0压缩包，可以在projects/n32wb452_EVAL/bsp/src/log.c文件内看到以下内容。

/*****************************************************************************
 * Copyright (c) 2019, Nations Technologies Inc.
 *
 * All rights reserved.
 * ****************************************************************************
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the disclaimer below.
 *
 * Nations' name may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY NATIONS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 * DISCLAIMED. IN NO EVENT SHALL NATIONS 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.
 * ****************************************************************************/

/**
 * [url=home.php?mod=space&uid=1455510]@file[/url] log.c
 * [url=home.php?mod=space&uid=40524]@author[/url] Nations
 * [url=home.php?mod=space&uid=644434]@version[/url] v1.0.1
 *
 * [url=home.php?mod=space&uid=855824]@copyright[/url] Copyright (c) 2019, Nations Technologies Inc. All rights reserved.
 */
#include "log.h"

#if LOG_ENABLE

void log_init(void) {
  GPIO_InitType GPIO_InitStructure;
  USART_InitType USART_InitStructure;

  // close JTAG

  RCC_EnableAPB2PeriphClk(RCC_APB2_PERIPH_AFIO | LOG_PERIPH_GPIO, ENABLE);
  if (LOG_REMAP) {
    if (LOG_REMAP == GPIO_RMP3_USART2) {
      // release PB4
      GPIO_ConfigPinRemap(GPIO_RMP_SW_JTAG_NO_NJTRST, ENABLE);
    }
    GPIO_ConfigPinRemap(LOG_REMAP, ENABLE);
  }

  LOG_ENABLE_PERIPH_CLK(LOG_PERIPH, ENABLE);

  GPIO_InitStructure.Pin = LOG_TX_PIN;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitPeripheral(LOG_GPIO, &GPIO_InitStructure);

  // GPIO_InitStructure.Pin       = LOG_RX_PIN;
  // GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  // GPIO_InitPeripheral(LOG_GPIO, &GPIO_InitStructure);

  USART_InitStructure.BaudRate = 115200;
  USART_InitStructure.WordLength = USART_WL_8B;
  USART_InitStructure.StopBits = USART_STPB_1;
  USART_InitStructure.Parity = USART_PE_NO;
  USART_InitStructure.HardwareFlowControl = USART_HFCTRL_NONE;
  USART_InitStructure.Mode = USART_MODE_TX;

  // init uart
  USART_Init(LOG_USARTx, &USART_InitStructure);

  // enable uart
  USART_Enable(LOG_USARTx, ENABLE);
}

static int is_lr_sent = 0;

int fputc(int ch, FILE *f) {
  if (ch == '\r') {
    is_lr_sent = 1;
  } else if (ch == '\n') {
    if (!is_lr_sent) {
      USART_SendData(LOG_USARTx, (uint8_t)'\r');
      /* Loop until the end of transmission */
      while (USART_GetFlagStatus(LOG_USARTx, USART_FLAG_TXDE) == RESET) {
      }
    }
    is_lr_sent = 0;
  } else {
    is_lr_sent = 0;
  }
  USART_SendData(LOG_USARTx, (uint8_t)ch);
  /* Loop until the end of transmission */
  while (USART_GetFlagStatus(LOG_USARTx, USART_FLAG_TXDE) == RESET) {
  }
  return ch;
}

#ifdef USE_FULL_ASSERT

__WEAK void assert_failed(const uint8_t *expr, const uint8_t *file,
                          uint32_t line) {
  log_error("assertion failed: `%s` at %s:%d", expr, file, line);
  while (1) {
  }
}
#endif // USE_FULL_ASSERT

#endif // LOG_ENABLE

这里我们可以看出，SDK源码通过projects/n32wb452_EVAL/bsp/inc/log.h里log串口部分定义，指定了log输出的串口，并重写了fputc，这样使用printf函数时，就会调用fputc，把内容输出到串口去。

现在我们要移植到腾讯TinyOS上，就需要将串口初始化部分代码调整到bsp目录里，然后在bsp代码里实现输出函数。

下面是调整后的代码（因个人书写习惯的原因，部分写法有区别）

#ifdef __GNUC__
/* With GCC, small printf (option LD Linker->Libraries->Small printf
   set to 'Yes') calls __io_putchar() */
#define PUTCHAR_PROTOTYPE int __io_putchar(char ch)
#define GETCHAR_PROTOTYPE int __io_getchar()
#else
#define PUTCHAR_PROTOTYPE int fputc(char ch)
#define GETCHAR_PROTOTYPE int fgetc()
#endif /* __GNUC__ */

static int is_lr_sent = 0;

PUTCHAR_PROTOTYPE {
    if (ch == '\r') {
        is_lr_sent = 1;
    } else if (ch == '\n') {
        if (!is_lr_sent) {
            USART_SendData(LOG_USARTx, (uint8_t)'\r');
            /* Loop until the end of transmission */
            while (USART_GetFlagStatus(LOG_USARTx, USART_FLAG_TXDE) == RESET) {
            }
        }
        is_lr_sent = 0;
    } else {
        is_lr_sent = 0;
    }
    USART_SendData(LOG_USARTx, (uint8_t)ch);
    /* Loop until the end of transmission */
    while (USART_GetFlagStatus(LOG_USARTx, USART_FLAG_TXDE) == RESET) {
    }
    return ch;
}

_write函数定义在utils组件中

int _write(int file, char *ptr, int len) {
    int DataIdx;
    for (DataIdx = 0; DataIdx < len; DataIdx++) {
        __io_putchar(*ptr++);
    }
    return len;
}

串口初始化代码调整到bsp目录，其他内容不变。
然后编译测试，可以得到正确的输出。