1.对于can的驱动函数文件加注释。在can（加注释）.c中标了“//2024.6”的语句加以理解并写出注释
can.c注释理解
can_init 【初始化CAN模块】
//=====================================================================
//函数名称：can_init
//函数返回：无
//参数说明：canNo：模块号，本芯片只有CAN_1
// canID：自身CAN节点的唯一标识，例如按照CANopen协议给出
// BitRate：位速率
//功能概要：初始化CAN模块
//=====================================================================
void can_init(uint8_t canNo, uint32_t canID, uint32_t BitRate)
{
//声明Init函数使用的局部变量
uint32_t CANMode;
uint32_t CANFilterBank;
uint32_t CANFiltermode;
uint32_t CAN_Filterscale;
//给Init函数使用的局部变量赋初值
CANMode = CAN_MODE_NORMAL; //2024.6 将CANMode(CAN总线工作模式)，设置为正常模式(CAN_MODE_NORMAL)
CANFilterBank = CANFilterBank0;
CANFiltermode = CAN_FILTERMODE_IDMASK;
CAN_Filterscale = CAN_FILTERSCALE_32BIT;
//（1）CAN总线硬件初始化
CAN_HWInit(CAN_CHANNEL);
//（2）CAN总线进入软件初始化模式
CAN_SWInit_Entry(canNo);
//（3）CAN总线模式设置
CAN_SWInit_CTLMode(canNo);
//（4）CAN总线位时序配置
CAN_SWInit_BT(canNo,CANMode,BitRate);
//（5）CAN总线过滤器初始化
CANFilterConfig(canNo, canID, CANFilterBank, CAN_RX_FIFO0, 1, CANFiltermode, CAN_Filterscale);
//（6）CAN总线退出软件初始化模式，进入正常模式
CAN_SWInit_Quit(canNo);
}
can_send 【CAN模块发送数据】
//=====================================================================
//函数名称：can_send
//函数返回：0=正常，1=错误
//参数说明：canNo：模块号，本芯片只有CAN_1
// DestID：目标CAN节点的唯一标识，例如按照CANopen协议给出
// len：待发送数据的字节数
// buff：待发送数据发送缓冲区首地址
//功能概要：CAN模块发送数据
//=====================================================================
uint8_t can_send(uint8_t canNo, uint32_t DestID, uint16_t len ,uint8_t* buff)
{
if(DestID > 0x1FFFFFFFU) return 1;
uint8_t send_length;
for(int i = len; i > 0; i = i-8) //通过循环将数据按 8 字节一段进行分次发送
{
send_length = (i>8)?8:i;
//can_send_once发一次函数判断状态寄存器来确定是否有空闲邮箱可用于存储待发送的数据,可用则返回0，反则返回1
if(can_send_once(canNo,DestID,send_length,buff+len-i) == 1) //2024.6
{
return 1;//当出现错误时返回1
}
}
return 0;//正常返回
}
can_recv【CAN模块接收数据】
//=====================================================================
//函数名称：can_recv
//函数返回：接收到的字节数
//参数说明：canNo：模块号，本芯片只有CAN_1
// buff：接收到的数据存放的内存区首地址
//功能概要：在CAN模块接收中断中调用本函数接收已经到达的数据
//=====================================================================
uint8_t can_recv(uint8_t canNo, uint8_t *buff)
{
uint8_t len;
uint32_t RxFifo = CAN_RX_FIFO0;
//（1）判断哪个邮箱收到了报文信息
if(RxFifo == CAN_RX_FIFO0)
{
if ((CAN_ARR[canNo-1]->RF0R & CAN_RF0R_FMP0) == 0U) //2024.6 判断CAN接收FIFO寄存器是否接受到信息，没有则为0
{
return 1;
}
}
else
{
if ((CAN_ARR[canNo-1]->RF1R & CAN_RF1R_FMP1) == 0U)
{
return 1;
}
}
//（2）获取数据长度
// 从特定的寄存器（CAN_RDT0R_DLC）和当前 FIFO 对应的邮箱的相关寄存器（RDTR）中获取并组合相关的位信息
// 然后通过右移操作，将提取到的信息按照预定义的位移量（CAN_RDT0R_DLC_Pos）进行位移，以得到准确的数据长度值，并将其赋值给变量 len
len = (CAN_RDT0R_DLC & CAN_ARR[canNo-1]->sFIFOMailBox[RxFifo].RDTR) >> CAN_RDT0R_DLC_Pos; //2024.6
//（3）获取数据帧中的数据
buff[0] = (uint8_t)((CAN_RDL0R_DATA0 & CAN_ARR[canNo-1]->sFIFOMailBox[RxFifo].RDLR) >> CAN_RDL0R_DATA0_Pos);
buff[1] = (uint8_t)((CAN_RDL0R_DATA1 & CAN_ARR[canNo-1]->sFIFOMailBox[RxFifo].RDLR) >> CAN_RDL0R_DATA1_Pos);
buff[2] = (uint8_t)((CAN_RDL0R_DATA2 & CAN_ARR[canNo-1]->sFIFOMailBox[RxFifo].RDLR) >> CAN_RDL0R_DATA2_Pos);
buff[3] = (uint8_t)((CAN_RDL0R_DATA3 & CAN_ARR[canNo-1]->sFIFOMailBox[RxFifo].RDLR) >> CAN_RDL0R_DATA3_Pos);
buff[4] = (uint8_t)((CAN_RDH0R_DATA4 & CAN_ARR[canNo-1]->sFIFOMailBox[RxFifo].RDHR) >> CAN_RDH0R_DATA4_Pos);
buff[5] = (uint8_t)((CAN_RDH0R_DATA5 & CAN_ARR[canNo-1]->sFIFOMailBox[RxFifo].RDHR) >> CAN_RDH0R_DATA5_Pos);
buff[6] = (uint8_t)((CAN_RDH0R_DATA6 & CAN_ARR[canNo-1]->sFIFOMailBox[RxFifo].RDHR) >> CAN_RDH0R_DATA6_Pos);
buff[7] = (uint8_t)((CAN_RDH0R_DATA7 & CAN_ARR[canNo-1]->sFIFOMailBox[RxFifo].RDHR) >> CAN_RDH0R_DATA7_Pos);
//（4）清除标志位，等待接收下一帧数据
if (RxFifo == CAN_RX_FIFO0)
{
SET_BIT(CAN_ARR[canNo-1]->RF0R, CAN_RF0R_RFOM0); //2024.6 RFOR寄存器置0清除标志位
}
else
{
SET_BIT(CAN_ARR[canNo-1]->RF1R, CAN_RF1R_RFOM1);
}
return len;
}
CAN_enable_re_int 【CAN接收中断开启】
//=====================================================================
//函数名称：CAN_enable_re_int
//函数返回：无
//参数说明：canNo:模块基地址号，Can_Rx_FifoNo:中断使用的邮箱号
//功能概要：CAN接收中断开启
//=====================================================================
void can_enable_recv_int(uint8_t canNo)
{
uint8_t Can_Rx_FifoNo;
Can_Rx_FifoNo = CAN_RX_FIFO0;
if(Can_Rx_FifoNo == CAN_RX_FIFO0) //通过 SET_BIT 函数设置 CAN_ARR[canNo-1]->IER 中的 CAN_IER_FMPIE0 位；否则设置 CAN_IER_FMPIE1 位
//这样可以根据指定的 FIFO 来针对性地开启相应的接收中断
SET_BIT(CAN_ARR[canNo-1]->IER, CAN_IER_FMPIE0); //2024.6
else
SET_BIT(CAN_ARR[canNo-1]->IER,CAN_IER_FMPIE1);
NVIC_EnableIRQ(table_irq_can[Can_Rx_FifoNo]); //2024.6 根据 table_irq_can[Can_Rx_FifoNo] 来使能对应的中断向量，以便在接收到相关中断时进行处理
}
can_send_once 【CAN模块发送一次数据】
//=====================================================================
//函数名称：can_send_once
//函数返回：0=正常，1=错误
//参数说明：canNo：模块号，本芯片只有CAN_1
// DestID：目标CAN节点的唯一标识，例如按照CANopen协议给出
// len：待发送数据的字节数
// buff：待发送数据发送缓冲区首地址
//功能概要：CAN模块发送一次数据
//=====================================================================
uint8_t can_send_once(uint8_t canNo, uint32_t DestID, uint16_t len ,uint8_t* buff)
{
//（1）定义Can发送函数所需要用到的变量
uint32_t transmit_mailbox;
uint32_t register_tsr;
uint32_t rtr;
rtr = CAN_RTR_DATA;
register_tsr = READ_REG(CAN_ARR[canNo-1]->TSR); //读取出tsr状态寄存器
//（2）判断3个邮箱中是否有空闲邮箱，若有，选取其中一个进行发送，选取顺序为1，2，3
if (((register_tsr & CAN_TSR_TME0) != 0U) ||
((register_tsr & CAN_TSR_TME1) != 0U) ||
((register_tsr & CAN_TSR_TME2) != 0U))
{
transmit_mailbox = (register_tsr & CAN_TSR_CODE) >> CAN_TSR_CODE_Pos; //2024.6 右移24为得到邮箱的号数[0/1/2]
if(transmit_mailbox > 2U)
{
return 1;
}
//（2.1）判断并设置发送帧为标准帧还是扩展帧
if(DestID <= 0x7FFU)
{
CAN_ARR[canNo-1]->sTxMailBox[transmit_mailbox].TIR = ((DestID << CAN_TI0R_STID_Pos)|CAN_ID_STD|rtr); //2024.6 邮箱TIR寄存器=左移21位|为标准位|数据帧
}
else
{
CAN_ARR[canNo-1]->sTxMailBox[transmit_mailbox].TIR = ((DestID << CAN_TI0R_EXID_Pos)|CAN_ID_EXT|rtr); //2024.6 不够就扩展
}
//（2.2）设置发送帧的数据长度
CAN_ARR[canNo-1]->sTxMailBox[transmit_mailbox].TDTR = len;
//SET_BIT(CAN_ARR[canNo-1]->sTxMailBox[transmit_mailbox].TDTR, CAN_TDT0R_TGT);
//（2.3）设置发送帧的数据
WRITE_REG(CAN_ARR[canNo-1]->sTxMailBox[transmit_mailbox].TDHR, //2024.6 高4字节送到TDHR
((uint32_t)buff[7] << CAN_TDH0R_DATA7_Pos) |
((uint32_t)buff[6] << CAN_TDH0R_DATA6_Pos) |
((uint32_t)buff[5] << CAN_TDH0R_DATA5_Pos) |
((uint32_t)buff[4] << CAN_TDH0R_DATA4_Pos));
WRITE_REG(CAN_ARR[canNo-1]->sTxMailBox[transmit_mailbox].TDLR, //低4字节送到TDLR
((uint32_t)buff[3] << CAN_TDL0R_DATA3_Pos) |
((uint32_t)buff[2] << CAN_TDL0R_DATA2_Pos) |
((uint32_t)buff[1] << CAN_TDL0R_DATA1_Pos) |
((uint32_t)buff[0] << CAN_TDL0R_DATA0_Pos));
//（2.4）发送Can数据报
SET_BIT(CAN_ARR[canNo-1]->sTxMailBox[transmit_mailbox].TIR, CAN_TI0R_TXRQ); //2024.6 TIR寄存器的TXRQ位置1，发送
return 0;
}
else
{
return 1;
}
}
CAN_HWInit 【CAN模块引脚初始化】
//=====================================================================
//函数名称：CAN_HWInit
//函数返回：0=正常，1=错误
//参数说明：CANChannel:硬件引脚组号，共有3组，分别为PTA11&PTA12(CAN_CHANNEL0),PTB8&PTB9(CAN_CHANNEL1),PTD0&PTD1(2)
//功能概要：CAN模块引脚初始化
//=====================================================================
uint8_t CAN_HWInit(uint8_t CANChannel)
{
if(CANChannel < 0 || CANChannel > 2)
{
return 1;
}
if(CANChannel == 0)
{
RCC->APB1ENR1 |= RCC_APB1ENR1_CAN1EN; //2024.6 使能CAN1的时钟
RCC->AHB2ENR |= RCC_AHB2ENR_GPIOAEN;
GPIOA->MODER &= ~(GPIO_MODER_MODE11|GPIO_MODER_MODE12);
GPIOA->MODER |= (GPIO_MODER_MODE11_1|GPIO_MODER_MODE12_1); //2024.6 配置GPIOA的11号和12号引脚为复用功能模式
GPIOA->AFR[1] &= ~(GPIO_AFRH_AFSEL11|GPIO_AFRH_AFSEL12);
GPIOA->AFR[1] |= (GPIO_AFRH_AFSEL11_0|GPIO_AFRH_AFSEL11_3)|(GPIO_AFRH_AFSEL12_0|GPIO_AFRH_AFSEL12_3);//2024.6
}
else if(CANChannel == 1)
{
RCC->APB1ENR1 |= RCC_APB1ENR1_CAN1EN;
RCC->AHB2ENR |= RCC_AHB2ENR_GPIOBEN;
GPIOB->MODER &= ~(GPIO_MODER_MODE8|GPIO_MODER_MODE9);
GPIOB->MODER |= (GPIO_MODER_MODE8_1|GPIO_MODER_MODE9_1);
GPIOB->AFR[1] &= ~(GPIO_AFRH_AFSEL8|GPIO_AFRH_AFSEL9);
GPIOB->AFR[1] |= ((GPIO_AFRH_AFSEL8_0|GPIO_AFRH_AFSEL8_3)|
(GPIO_AFRH_AFSEL9_0|GPIO_AFRH_AFSEL9_3));
}
else
{
RCC->APB1ENR1 |= RCC_APB1ENR1_CAN1EN;
RCC->AHB2ENR |= RCC_AHB2ENR_GPIODEN;
GPIOD->MODER &= ~(GPIO_MODER_MODE0|GPIO_MODER_MODE1);
GPIOD->MODER |= (GPIO_MODER_MODE0_1|GPIO_MODER_MODE1_1);
GPIOD->AFR[0] &= ~(GPIO_AFRL_AFSEL0|GPIO_AFRL_AFSEL1);
GPIOD->AFR[0] |= ((GPIO_AFRL_AFSEL0_0 | GPIO_AFRL_AFSEL0_3)|
(GPIO_AFRL_AFSEL1_0 | GPIO_AFRL_AFSEL1_3));
}
return 0;
}
CAN_SWInit_Entry 【进入初始化模式】
//=====================================================================
//函数名称：CAN_SWInit_Entry
//函数返回：0=正常，1=错误
//参数说明：canNo:模块基地址号，本芯片只有CAN_1,
//功能概要：进入初始化模式
//=====================================================================
uint8_t CAN_SWInit_Entry(uint8_t canNo)
{
int i;
CLEAR_BIT(CAN_ARR[canNo-1]->MCR, CAN_MCR_SLEEP); //2024.6 清除CAN控制寄存器(MCR)中的SLEEP位以退出睡眠模式
i = 0;
while ((CAN_ARR[canNo-1]->MSR & CAN_MSR_SLAK) != 0U) //2024.6 等待CAN模块退出睡眠模式，检查MSR寄存器的SLAK位
{
if(i++ > 0x30000)
{
return 1;
}
}
SET_BIT(CAN_ARR[canNo-1]->MCR, CAN_MCR_INRQ); //2024.6 设置CAN控制寄存器(MCR)中的INRQ位以进入初始化模式
i = 0;
while ((CAN_ARR[canNo-1]->MSR & CAN_MSR_INAK) == 0U)
{
if(i++ > 0x30000)
{
return 1;
}
}
return 0;
}
CAN_SWInit_CTLMode 【CAN总线模式设置
//=====================================================================
//函数名称：CAN_SWInit_CTLMode
//函数返回：无
//参数说明：canNo:模块基地址号，本芯片只有CAN_1,
//功能概要：CAN总线模式设置
//=====================================================================
void CAN_SWInit_CTLMode(uint8_t canNo)
{
CLEAR_BIT(CAN_ARR[canNo-1]->MCR, CAN_MCR_TTCM); //2024.6 清除CAN控制寄存器(MCR)中的TTCM位 (时间触发通信模式)
CLEAR_BIT(CAN_ARR[canNo-1]->MCR, CAN_MCR_ABOM); //2024.6 清除CAN控制寄存器(MCR)中的ABOM位 (自动总线关闭管理)
CLEAR_BIT(CAN_ARR[canNo-1]->MCR, CAN_MCR_AWUM); //2024.6 清除CAN控制寄存器(MCR)中的AWUM位 (自动唤醒模式)
SET_BIT(CAN_ARR[canNo-1]->MCR, CAN_MCR_NART); //2024.6 设置CAN控制寄存器(MCR)中的NART位 (禁止自动重传)
CLEAR_BIT(CAN_ARR[canNo-1]->MCR, CAN_MCR_RFLM); //2024.6 清除CAN控制寄存器(MCR)中的RFLM位 (接收FIFO锁定模式)
CLEAR_BIT(CAN_ARR[canNo-1]->MCR, CAN_MCR_TXFP); //2024.6 清除CAN控制寄存器(MCR)中的TXFP位 (发送FIFO优先级)
}
CAN_SWInit_CTLMode 【CAN总线位时序配置】
//函数名称：CAN_SWInit_CTLMode
//函数返回：无
//参数说明：canNo:模块基地址号，本芯片只有CAN_1,
//CANMode:CAN总线工作模式，分别为正常模式(CAN_MODE_NORMAL)、回环模式(CAN_MODE_LOOPBACK)、
//静默模式(CAN_MODE_SILENT)以及回环与静默组合模式(CAN_MODE_SILENT_LOOPBACK)
//功能概要：CAN总线位时序配置
void CAN_SWInit_BT(uint8_t canNo, uint32_t CANMode, uint32_t Prescaler)
{
CAN_ARR[canNo-1]->BTR |= ((uint32_t)(Prescaler-1)|CAN_SJW_1TQ|CAN_BTR_TS1_1|CAN_BTR_TS1_0|CAN_BTR_TS2_2|CANMode); //2024.6 配置CAN位时序寄存器 (BTR)
}
CAN_SWInit_Quit 【退出初始化模式】
//=====================================================================
//函数名称：CAN_SWInit_Quit
//函数返回：0=正常，1=错误
//参数说明：canNo:模块基地址号
//功能概要：退出初始化模式，进入正常模式
//=====================================================================
uint8_t CAN_SWInit_Quit(uint8_t canNo)
{
int i;
CLEAR_BIT(CAN_ARR[canNo-1]->MCR, CAN_MCR_INRQ); //2024.6 清除CAN控制寄存器(MCR)中的INRQ位以退出初始化模式
i = 0;
while ((CAN_ARR[canNo-1]->MSR & CAN_MSR_INAK) != 0U) //2024.6 等待CAN模块退出初始化模式，检查MSR寄存器的INAK位
{
// 如果等待时间超过限制，返回错误代码1
if (i++ > 0x30000)
{
return 1;
}
}
return 0;
}
CANFilterConfig 【CAN接收中断开启】
//=====================================================================
//函数名称： CANFilterConfig
//函数返回：0=正常，1=错误
//参数说明： canNo:模块基地址号，
// canID：自身CAN节点的唯一标识，例如按照CANopen协议给出
// Can_Rx_FifoNo:中断使用的邮箱号，
// IsActivate:是否激活过滤器
// CANFilterBank:CAN总线过滤器组选择,共有28个,(CANFilterBank0~CANFilterBank27)
// CANFiltermode:CAN总线过滤器模式，分别为掩码模式(CAN_FILTERMODE_IDMASK)和列表模式(CAN_FILTERMODE_IDLIST)
// CAN_Filterscale:CAN总线过滤器位数，分别为32位(CAN_FILTERSCALE_32BIT)和16位(CAN_FILTERSCALE_16BIT)
//功能概要：CAN接收中断开启
//=====================================================================
uint8_t CANFilterConfig(uint8_t canNo, uint32_t CanID, uint32_t FilterBank, uint32_t Can_Rx_FifoNo, uint8_t IsActivate, uint32_t FilterMode, uint32_t FilterScale)
{
uint32_t FilterIdHigh, FilterIdLow, FilterMaskIdHigh, FilterMaskIdLow, filternbrbitpos;
if(CanID <= 0x7FFU) CanID = CanID << CAN_TI0R_STID_Pos; //2024.6 如果CAN ID小于等于0x7FF（标准帧），将ID左移到标准帧位置
FilterIdHigh = (CanID >> 16) & 0xFFFF; //2024.6 高16位过滤器ID设置
FilterIdLow = (CanID & 0xFFFF); //2024.6 低16位过滤器ID设置
FilterMaskIdHigh = 0xFFE0; //2024.6 高16位掩码ID设置
FilterMaskIdLow = 0x0000; //2024.6 低16位掩码ID设置
filternbrbitpos = (uint32_t)1 << (FilterBank & 0x1FU); //2024.6 计算过滤器号位置掩码
SET_BIT(CAN_ARR[canNo-1]->FMR, CAN_FMR_FINIT); //2024.6 设置过滤器初始化模式 (FINIT=1),在此模式下可以进行过滤器初始化
CLEAR_BIT(CAN_ARR[canNo-1]->FA1R, filternbrbitpos); //2024.6 禁用过滤器
// 根据过滤器位数配置过滤器寄存器
if (FilterScale == CAN_FILTERSCALE_16BIT) // 16位模式
{
CLEAR_BIT(CAN_ARR[canNo-1]->FS1R, filternbrbitpos);
CAN_ARR[canNo-1]->sFilterRegister[FilterBank].FR1 =
((0x0000FFFFU & (uint32_t)FilterMaskIdLow) << 16U) |
(0x0000FFFFU & (uint32_t)FilterIdLow);
CAN_ARR[canNo-1]->sFilterRegister[FilterBank].FR2 =
((0x0000FFFFU & (uint32_t)FilterMaskIdHigh) << 16U) |
(0x0000FFFFU & (uint32_t)FilterIdHigh);
}
if (FilterScale == CAN_FILTERSCALE_32BIT) //2024.6 32位模式
{
SET_BIT(CAN_ARR[canNo-1]->FS1R, filternbrbitpos); //2024.6
CAN_ARR[canNo-1]->sFilterRegister[FilterBank].FR1 = //2024.6
((0x0000FFFFU & (uint32_t)FilterIdHigh) << 16U) |
(0x0000FFFFU & (uint32_t)FilterIdLow);
CAN_ARR[canNo-1]->sFilterRegister[FilterBank].FR2 =
((0x0000FFFFU & (uint32_t)FilterMaskIdHigh) << 16U) |
(0x0000FFFFU & (uint32_t)FilterMaskIdLow);
}
//CANFiltermode:CAN总线过滤器模式，分别为掩码模式(CAN_FILTERMODE_IDMASK)和列表模式(CAN_FILTERMODE_IDLIST)
if (FilterMode == CAN_FILTERMODE_IDMASK) //2024.6 根据过滤器模式设置
{
CLEAR_BIT(CAN_ARR[canNo-1]->FM1R, filternbrbitpos); //2024.6 掩码模式
}
else
{
SET_BIT(CAN_ARR[canNo-1]->FM1R, filternbrbitpos); // 列表模式
}
//Can_Rx_FifoNo:中断使用的邮箱号
if (Can_Rx_FifoNo == CAN_FILTER_FIFO0) //2024.6 根据接收FIFO邮箱号设置
{
CLEAR_BIT(CAN_ARR[canNo-1]->FFA1R, filternbrbitpos); //2024.6 使用FIFO0
}
else
{
SET_BIT(CAN_ARR[canNo-1]->FFA1R, filternbrbitpos); //使用FIFO1
}
//IsActivate:是否激活过滤器
if (IsActivate == 1) //2024.6 激活过滤器
{
SET_BIT(CAN_ARR[canNo-1]->FA1R, filternbrbitpos); //2024.6 设置FAIR位,以激活过滤器(CAN filter activation register)
}
//退出过滤器初始化模式 (FINIT=0)
CLEAR_BIT(CAN_ARR[canNo-1]->FMR, CAN_FMR_FINIT); //2024.6 清除FMR位，退出过滤器初始化模式
return 0;
}
2. 2个或以上同学相互连接，利用CAN通信，向对方发送带有本人姓名的信息。
实验原理图
连线方式：按基本原理性电路（不带收发器芯片）连接，参考教材图10-1
- 提醒！！！注意二极管的方向，容易弄混
连线照片
结果截图
- 补充说明：实验时未加上换行符“\r\n”，所以显示结果都是连在一起的
