【FM33LG0系列开发板测评】06.CAN

xld0932 发表于 2021-12-16 20:17

1、简介 
FM33LG048带有一路CNA（控制器区域网络）接口，支持CAN 2.0A和CAN 2.0B标准，支持11位的标准ID和29位的扩展ID；最高传输速率可以达到1Mbps，同时具有2个发送FIFO、2个接收FIFO和4个接收滤波器；在总线错误或者传输仲裁失败的情况下，还支持自动重发的功能。

FM33LG0xx DEMO V1.1开发板上将FM33LG048的CAN接口通过排针的形式接出来了，分别是PD10（CAN_RX）、PE9（CAN_TX），对应开发板上的J17这个接口；

FM33LG048的CAN时钟源有多种选择：RCHF、XTHF、PLL、APBCLK；选择哪一个时钟源是可以通过软件来配置的；为了提高通讯速率的精准度，使用的时钟频率需要满足ISO11898-1规定的容差范围，本例程中使用了XTHF外部晶振作为CAN的时钟源，所以在初始化CAN配置参数的时候，需要先配置XTHF使能。

 

2、软件功能 
使用XTHF外部晶振作为CAN的时钟源，将CAN的通讯速率配置为100kbps，程序中每间隔500ms向CAN总线上发送一条测试数据；开启CAN接收中断，在有接收到新数据时，通过串口打印出CAN收到的数据信息；

 

3、实现代码

<pre>
<code class="language-cpp">/*******************************************************************************
* @file CAN.c
* @authorKing
* @version V1.00
* @date 27-Nov-2021
* @brief ......
*******************************************************************************/

/* Define to prevent recursive inclusion -------------------------------------*/
#define __CAN_C__

/* Includes ------------------------------------------------------------------*/
#include "CAN.h"

#if CAN_ENABLE

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/

/* Exported variables --------------------------------------------------------*/
/* Exported function prototypes ----------------------------------------------*/

/*******************************************************************************
* @brief
* @param
* @retval
* @attention *******************************************************************************/
void CAN_Configure(void)
{
FL_GPIO_InitTypeDef GPIO_InitStruct;
FL_CAN_InitTypeDef CAN_InitStruct;
FL_CAN_FilterInitTypeDef CAN_FilterInitStruct;

//---Enable XTHF For CAN Clock Source
FL_GPIO_StructInit(&GPIO_InitStruct);
GPIO_InitStruct.pin = FL_GPIO_PIN_2 | FL_GPIO_PIN_3;
GPIO_InitStruct.mode = FL_GPIO_MODE_ANALOG;
GPIO_InitStruct.outputType = FL_GPIO_OUTPUT_PUSHPULL;
FL_GPIO_Init(GPIOC, &GPIO_InitStruct);

FL_CMU_XTHF_Enable();
FL_CMU_XTHF_WriteDriverStrength(0x1F);
FL_DelayMs(3);

FL_GPIO_StructInit(&GPIO_InitStruct);
GPIO_InitStruct.pin = FL_GPIO_PIN_9;
GPIO_InitStruct.mode = FL_GPIO_MODE_DIGITAL;
GPIO_InitStruct.outputType = FL_GPIO_OUTPUT_PUSHPULL;
GPIO_InitStruct.pull = FL_ENABLE;
FL_GPIO_Init(GPIOE, &GPIO_InitStruct);

FL_GPIO_StructInit(&GPIO_InitStruct);
GPIO_InitStruct.pin = FL_GPIO_PIN_10;
GPIO_InitStruct.mode = FL_GPIO_MODE_DIGITAL;
GPIO_InitStruct.outputType = FL_GPIO_OUTPUT_PUSHPULL;
GPIO_InitStruct.pull = FL_ENABLE;
FL_GPIO_Init(GPIOD, &GPIO_InitStruct);

/* CAN Baudrate = CAN_CLK / (BRP + 1) / (TS1 + TS2 + 1) */
FL_CAN_StructInit(&CAN_InitStruct);
CAN_InitStruct.mode = FL_CAN_MODE_NORMAL;
CAN_InitStruct.BRP = 7;
CAN_InitStruct.clockSource = FL_CMU_CAN_CLK_SOURCE_XTHF;
CAN_InitStruct.SJW = FL_CAN_SJW_1Tq;
CAN_InitStruct.TS1 = FL_CAN_TS1_5Tq;
CAN_InitStruct.TS2 = FL_CAN_TS2_4Tq;
FL_CAN_Init(CAN, &CAN_InitStruct);

FL_CAN_StructFilterInit(&CAN_FilterInitStruct);
CAN_FilterInitStruct.filterIdStandard = 0x6AD;
CAN_FilterInitStruct.filterIdSRR = 0;
CAN_FilterInitStruct.filterIdIDE = 0;
CAN_FilterInitStruct.filterIdRTR = 0;

CAN_FilterInitStruct.filterMaskIdHigh = 0x7FF;
CAN_FilterInitStruct.filterMaskIdSRR= 0x01;
CAN_FilterInitStruct.filterMaskIdIDE= 0x01;
CAN_FilterInitStruct.filterMaskIdRTR= 0x01;
CAN_FilterInitStruct.filterEn = FL_ENABLE;
FL_CAN_FilterInit(CAN, &CAN_FilterInitStruct, FL_CAN_FILTER1);

FL_CAN_ClearFlag_CRXOK(CAN);
FL_CAN_EnableIT_RXOK(CAN);

NVIC_DisableIRQ(CAN_IRQn);
NVIC_SetPriority(CAN_IRQn, 2);
NVIC_EnableIRQ(CAN_IRQn);

TASK_Append(TASK_ID_CAN, CAN_Handler, 500);
}

/*******************************************************************************
* @brief
* @param
* @retval
* @attention
*******************************************************************************/
void FL_CAN_FIFO_Write(uint32_t ID, uint32_t Length, uint32_t Data1, uint32_t Data2)
{
uint32_t Timeout = 5;

while((FL_CAN_IsActiveFlag_TXBuffFull(CAN) != FL_RESET) & Timeout)
{
 Timeout--;
 FL_DelayMs(1);
}

FL_CAN_WriteTXMessageID(CAN, ID);
FL_CAN_WriteTXMessageLength(CAN, Length);
FL_CAN_WriteTXMessageWord1(CAN, Data1);
FL_CAN_WriteTXMessageWord2(CAN, Data2);
}

/*******************************************************************************
* @brief
* @param
* @retval
* @attention
*******************************************************************************/
void FL_CAN_HPBUF_Write(uint32_t ID, uint32_t Length, uint32_t Data1, uint32_t Data2)
{
uint32_t Timeout = 5;

while((FL_CAN_IsActiveFlag_TXHighPriorBuffFull(CAN) != FL_RESET) & Timeout)
{
 Timeout--;
 FL_DelayMs(1);
}

FL_CAN_WriteHighPriorTXMessageID(CAN, ID);
FL_CAN_WriteHighPriorMessageLength(CAN, Length);
FL_CAN_WriteHighPriorMessageWord1(CAN, Data1);
FL_CAN_WriteHighPriorMessageWord2(CAN, Data2);
}

/*******************************************************************************
* @brief
* @param
* @retval
* @attention
*******************************************************************************/
void FL_CAN_Receive(void)
{
uint32_t Data1 = 0;
uint32_t Data2 = 0;

CAN_MSG_TypeDef RxMessage;

RxMessage.StdId = FL_CAN_ReadRXMessageID(CAN);
RxMessage.DLC = FL_CAN_ReadRXMessageLength(CAN);

Data1 = FL_CAN_ReadRXMessageWord1(CAN);
Data2 = FL_CAN_ReadRXMessageWord2(CAN);

RxMessage.Data = (uint8_t)(Data1 >> 0x00) & 0xFF;
RxMessage.Data = (uint8_t)(Data1 >> 0x08) & 0xFF;
RxMessage.Data = (uint8_t)(Data1 >> 0x10) & 0xFF;
RxMessage.Data = (uint8_t)(Data1 >> 0x18) & 0xFF;
RxMessage.Data = (uint8_t)(Data2 >> 0x00) & 0xFF;
RxMessage.Data = (uint8_t)(Data2 >> 0x08) & 0xFF;
RxMessage.Data = (uint8_t)(Data2 >> 0x10) & 0xFF;
RxMessage.Data = (uint8_t)(Data2 >> 0x18) & 0xFF;

printf("\r\nCAN Receive : 0x%x, %d, ", RxMessage.StdId, RxMessage.DLC);

for(uint32_t i = 0; i < 8; i++)
{
 printf("%02x ", RxMessage.Data);

}

printf("\r\n");
}

/*******************************************************************************
* @brief
* @param
* @retval
* @attention
*******************************************************************************/
void FL_CAN_Transmit(uint32_t FrameFormat, CAN_MSG_TypeDef *TxMessage)
{
uint32_t ID = 0;
uint32_t Length = 0;
uint32_t Data1 = 0;
uint32_t Data2 = 0;

if(FrameFormat == FL_CAN_FORMAT_STANDARD_DATA)
{
 ID = TxMessage->StdId & 0x7FF;
}

else if(FrameFormat == FL_CAN_FORMAT_STANDARD_REMOTE)
{
 ID = (TxMessage->StdId & 0x7FF) | (1 << 11);
}

else if(FrameFormat == FL_CAN_FORMAT_EXTEND_DATA)
{
 ID = ((TxMessage->ExtId & 0x3FFFF) << 13) |
 ((uint32_t)1 << 12) |
 ((uint32_t)1 << 11) |
 ((TxMessage->ExtId & 0x1FFC0000) >> 18);
}

else if(FrameFormat == FL_CAN_FORMAT_EXTEND_REMOTE)
{
 ID = ((TxMessage->ExtId & 0x3FFFF) << 13) |
 ((uint32_t)1 << 12) |
 ((uint32_t)1 << 31) |
 ((TxMessage->ExtId & 0x1FFC0000) >> 18);
}

Length = TxMessage->DLC;

Data1 = ((uint32_t)TxMessage->Data << 0x18) |
 ((uint32_t)TxMessage->Data << 0x10) |
 ((uint32_t)TxMessage->Data << 0x08) |
 ((uint32_t)TxMessage->Data << 0x00);

Data2 = ((uint32_t)TxMessage->Data << 0x18) |
 ((uint32_t)TxMessage->Data << 0x10) |
 ((uint32_t)TxMessage->Data << 0x08) |
 ((uint32_t)TxMessage->Data << 0x00);

#if 1
FL_CAN_FIFO_Write(ID, Length, Data1, Data2);
#else
FL_CAN_HPBUF_Write(ID, Length, Data1, Data2);
#endif
}

/*******************************************************************************
* @brief
* @param
* @retval
* @attention
*******************************************************************************/
void CAN_Handler(void)
{
CAN_MSG_TypeDef TxMessage;

TxMessage.StdId = 0x6AD;
TxMessage.DLC = 8;

for(uint8_t i = 0; i < TxMessage.DLC; i++)
{
 TxMessage.Data = i;
}

FL_CAN_Transmit(FL_CAN_FORMAT_STANDARD_DATA, &TxMessage);
}

/*******************************************************************************
* @brief
* @param
* @retval
* @attention
*******************************************************************************/
void CAN_IRQHandler(void)
{
if((FL_ENABLE == FL_CAN_IsEnabledIT_RXOK(CAN)) &&
 (FL_SET == FL_CAN_IsActiveFlag_RXOK(CAN)))
{
 FL_CAN_Receive();
 FL_CAN_ClearFlag_CRXOK(CAN);
}
}

#endif

/******************* (C) COPYRIGHT 2021 *************************END OF FILE***/

</code></pre>

 

4、调试运行

由于开发板本身没有带有CAN收发器，所以我们在进行CAN实验的时候，需要外接一个CAN收发模块；本实验选用的VP230这个芯片，支持与MCU相同的3.3V工作电压；另外再连接一个CAN调试工具，与PC端的软件进行配合，查看CAN总线上传输的数据、或者是向CAN总线上发送测试数据等操作。

4.1.硬件连线



 

4.2.监测数据



 

4.3.接收数据



 

5、工程源码

fiee 发表于 2023-4-21 15:50

大佬你好，看你log上打印的是理论上PLL倍频完的频率？是超过这个芯片的最大主频限制了吗?

xld0932 发表于 2023-4-23 15:37

fiee 发表于 2023-4-21 15:50
大佬你好，看你log上打印的是理论上PLL倍频完的频率？是超过这个芯片的最大主频限制了吗?

<img height="48" src="https://bbs.eeworld.com.cn/static/editor/plugins/hkemoji/sticker/facebook/puzzle.gif" width="53" />

 

8000000Hz = 8MHz，有超过吗？

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【FM33LG0系列开发板测评】06.CAN