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AT32 MCU上使用DMA传输数据加速进行CRC计算


示例目的
演示在AT32 MCU上使用DMA传输数据加速进行CRC计算，支持CRC8,CRC16，CRC32。
支持型号列表：
支持型号 AT32 全系列
主要使用外设
CRC
DMA
USART
GPIO


快速使用方法
硬件资源
1) USART1(PA9/PA10)
2) AT-START实验板，如下是AT-START-F403A开发板。


软件资源
1) SourceCode
 SC0150_SourceCode
2) Doc
 SC0150_AT32_CRC_computing_by_using_DMA 使用方法。
Note: 所有project 都是基于keil 5 而建立，若用户需要在其他编译环境上使用，请参考
AT32F407_Firmware_Library_V2.x.x/project/at_start_f407/templates 中各种编译环境（例如
IAR6/7,keil 4/5）进行简单修改即可。
示例使用
1) 打开SC0150_SourceCode_V2.0.0\utilities\crc_dma\mdk_v5源程序。
2) 编译并下载到目标开发板，接上串口（PA9/PA10）。
3) 计算结果会从串口打印输出。


相关代码

#include "at32f403a_407_board.h"

#include "at32f403a_407_clock.h"

/** @addtogroup UTILITIES_examples

  * @{

  */

/** @addtogroup CRC_dma_demo

  * @{

  */

confirm_state dma_done_flag = FALSE;

uint8_t data_buffer[]  = {0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xAA, 0xBB};

/**

  * [url=home.php?mod=space&uid=247401]@brief[/url]  calculate 8-bit data CRC.

  * @param  pbuffer: pointer to the buffer containing the data to be computed.

  * @param  length: length of the buffer to be computed.

  * @retval crc

  */

uint32_t crc8_block_calculate(uint8_t *pbuffer, uint32_t length)

{

  uint32_t index = 0;

  for(index = 0; index < length; index++)

  {

    (*(uint8_t *)&CRC->dt) = pbuffer[index];

  }

  return (CRC->dt);

}

/**

  * [url=home.php?mod=space&uid=247401]@brief[/url]  calculate 16-bit data CRC.

  * @param  pbuffer: pointer to the buffer containing the data to be computed.

  * @param  length: length of the buffer to be computed.

  * @retval crc

  */

uint32_t crc16_block_calculate(uint16_t *pbuffer, uint32_t length)

{

  uint32_t index = 0;

  for(index = 0; index < length; index++)

  {

    (*(uint16_t *)&CRC->dt) = pbuffer[index];

  }

  return (CRC->dt);

}

/**

  * [url=home.php?mod=space&uid=247401]@brief[/url]  config nvic.

  * @param  none

  * @retval none

  */

void nvic_config(void)

{

  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);

  nvic_irq_enable(DMA1_Channel1_IRQn, 1, 0);

}

/**

  * @brief  config crc.

  * @param  none

  * @retval none

  */

void crc_config(void)

{

  crm_periph_clock_enable(CRM_CRC_PERIPH_CLOCK, TRUE);

  crc_init_data_set(0xFFFFFFFF);

  crc_poly_value_set(0x04C11DB7);

  crc_reverse_output_data_set(CRC_REVERSE_OUTPUT_DATA);

}

/**

  * @brief  config dma, using DMA1_CHANNEL1.

  * @param  none

  * @retval none

  */

void dma_config(void)

{

  dma_init_type dma_init_struct = {0};

  crm_periph_clock_enable(CRM_DMA1_PERIPH_CLOCK, TRUE);

  dma_reset(DMA1_CHANNEL1);

  dma_default_para_init(&dma_init_struct);

  dma_init_struct.direction = DMA_DIR_MEMORY_TO_MEMORY;

  dma_init_struct.memory_inc_enable = FALSE;

  dma_init_struct.peripheral_inc_enable = TRUE;

  dma_init_struct.priority = DMA_PRIORITY_MEDIUM;

  dma_init_struct.loop_mode_enable = FALSE;

  dma_init(DMA1_CHANNEL1, &dma_init_struct);

  dma_interrupt_enable(DMA1_CHANNEL1, DMA_FDT_INT, TRUE);

  dma_channel_enable(DMA1_CHANNEL1, FALSE);

}

/**

  * @brief  calculate CRC with dma mode.

  * @param  pbuff: pointer of data buffer.

  * @param  length: data buffer length

  * @retval none

  */

uint32_t dma_calculate(uint8_t *pbuff, uint32_t length)

{

  crc_data_reset();

  crc_reverse_input_data_set(CRC_REVERSE_INPUT_BY_WORD);

  DMA1_CHANNEL1->dtcnt = length;

  DMA1_CHANNEL1->maddr = (uint32_t)&(CRC->dt);

  DMA1_CHANNEL1->ctrl_bit.mwidth = DMA_MEMORY_DATA_WIDTH_BYTE;

  DMA1_CHANNEL1->paddr = (uint32_t)pbuff;

  DMA1_CHANNEL1->ctrl_bit.pwidth = DMA_PERIPHERAL_DATA_WIDTH_BYTE;

  dma_done_flag = FALSE;

  dma_channel_enable(DMA1_CHANNEL1, TRUE);

  /* waiting dma complete */

  while(dma_done_flag == FALSE);

  return crc_data_get();

}

/**

  * @brief  calculate CRC with polling mode.

  * @param  pbuff: pointer of data buffer.

  * @param  length: data buffer length

  * @retval none

  */

uint32_t poll_calculate(uint8_t *pbuff, uint32_t length)

{

  crc_data_reset();

  /* word */

  if(length > 3)

  {

    crc_reverse_input_data_set(CRC_REVERSE_INPUT_BY_WORD);

    crc_block_calculate((uint32_t *)pbuff, length / 4);

    pbuff = pbuff + ((length / 4) * 4);

    length = length % 4;

  }

  /* halfword */

  if(length > 2)

  {

    crc_reverse_input_data_set(CRC_REVERSE_INPUT_BY_HALFWORD);

    crc16_block_calculate((uint16_t *)pbuff, 1);

    pbuff = pbuff + 2;

    length = length - 2;

  }

  /* byte */

  if(length > 0)

  {

    crc_reverse_input_data_set(CRC_REVERSE_INPUT_BY_BYTE);

    crc8_block_calculate((uint8_t *)pbuff, 1);

    length = 0;

  }

  return crc_data_get();

}

/**

  * @brief  main function.

  * @param  none

  * @retval none

  */

int main(void)

{

  uint32_t crc_result = 0;

  system_clock_config();

  at32_board_init();

  uart_print_init(115200);

  nvic_config();

  crc_config();

  dma_config();

  /* calculate CRC-32 using dma and polling mode */

  crc_poly_size_set(CRC_POLY_SIZE_32B);

  crc_result = dma_calculate(data_buffer, sizeof(data_buffer));

  printf("crc32 dma result: 0x%x\n", crc_result);

  crc_result = poll_calculate(data_buffer, sizeof(data_buffer));

  printf("crc32 poll result: 0x%x\n", crc_result);

  /* calculate CRC-16 using dma and polling mode */

  crc_poly_size_set(CRC_POLY_SIZE_16B);

  crc_result = dma_calculate(data_buffer, sizeof(data_buffer));

  printf("crc16 dma result: 0x%x\n", crc_result);

  crc_result = poll_calculate(data_buffer, sizeof(data_buffer));

  printf("crc16 poll result: 0x%x\n", crc_result);

  /* calculate CRC-8 using dma and polling mode */

  crc_poly_size_set(CRC_POLY_SIZE_8B);

  crc_result = dma_calculate(data_buffer, sizeof(data_buffer));

  printf("crc8 dma result: 0x%x\n", crc_result);

  crc_result = poll_calculate(data_buffer, sizeof(data_buffer));

  printf("crc8 poll result: 0x%x\n", crc_result);

  while(1)

  {

  }

}