MPC 5748 CANFD

徐工2024 — Sat, 29 Jun 2024 05:58:05 GMT

您好，我最近在测试MPC5748G的CANFD功能，能实现它的发送以及接收中断功能，但是目前遇到的问题是，我无法使用block块1/2来进行发送数据，只能使用block0才能发送数据，如下是我的代码：

void FlexCAN0_Init(void)

{

uint32_t i = 0;

/* enable the FlexCAN module, reset and freeze */

CAN_0.MCR.R = (0

| CAN_MCR_FRZ /* enabled to enter Freeze mode */

| CAN_MCR_HALT /* enter freeze mode if FRZ bit is set */

//| CAN_MCR_SOFTRST /* soft reset */

//| CAN_MCR_SRXDIS /* self reception enabled */

| CAN_MCR_BCC /* individual Rx masking and queue */

| 0x0000001F);

/* double check that we are actually in freeze mode */

while(0 == CAN_0.MCR.B.FRZACK) {};

while(0 == CAN_0.MCR.B.NOTRDY) {};

CAN_0.MCR.R = (0

| CAN_MCR_FRZ /* enabled to enter Freeze mode */

| CAN_MCR_HALT /* enter freeze mode if FRZ bit is set */

/*| CAN_MCR_SRXDIS */ /* self reception enabled */

| CAN_MCR_BCC /* individual Rx masking and queue */

| CAN_MCR_AEN /* Safe Tx abort enable */

| CAN_MCR_FDEN /* CAN FD enabled */

| 0x0000001F); /* enable 32 MBs */

//CAN_0.CBT.R = 0x802D29AD; // Nominal bit time: 40 MHz clksrc, 500K bps with 40 tq

// EPRESDIV = 1, EPROPSEG = 10, EPSEG1 = 13, EPREG2 = 13

CAN_0.CBT.R = 0x80272A67; // bitrate=500kbps, CPI clk=40 MHz; Prescaler= 2, PROPSEG=11, PSEG1=20, PSEG2=8, RJW=8, smp=80%

CAN_0.FDCBT.R = 0x00111421; // bitrateFD=2000kbps, CPI clk=40 MHz; fPrescaler= 2, fPROPSEG=5, fPSEG1=2, fPSEG2=2, fRJW=2, smp=80%

//CAN_0.FDCBT.R = 0x00130862; // Data bit time: 40 MHz clksrc, 2Mbps with 10 tq

// FPRESDIV = 1, FPROPSEG = 2, FPSEG1 = 3, FPREG2 = 4

//CAN_0.FDCBT.R = 0x00330425;

CAN_0.FDCTRL.R = 0x8030000; // bit rate switching enable, 64byte payload for region 0

// CAN_0.FDCTRL.B.MBDSR1 = 3; // TCD disabled

/* clear MB are for first 32MBs */

for(i=0;i<(32*4);i++)

{

CAN_0.RAMn[i].R = 0;

}

/* set mask registers - all ID bits must match */

for(i=0;i<32;i++)

{

CAN_0.RXIMR[i].R = 0x1FFFFFFF;

}

CAN_0.CTRL2.R |= 0x1000; // set ISOCANFDEN bit 大端

/*enable interrupt for MB3*/

CAN_0.IMASK1.R = 0x00000004; //小端

/* Finally clear the HALT flag in MCR to enable the FlexCAN

* to synchronize with the CAN bus and allow

* participation in communication. */

CAN_0.MCR.B.HALT = 0;

/* wait until FlexCAN ready */

while(1 == CAN_0.MCR.B.FRZACK){};

while(1 == CAN_0.MCR.B.NOTRDY){};

}

/*******************************************************************************

Function Name : GetMBAddr

Engineer : Petr Stancik

Date : Jun-22-2021

Parameters : mb ... mb number used

Modifies : NONE

Returns : address of MB

Notes : get address of selected MB depending on payload set for memory block

memory block 0 is only checked

Issues : NONE

*******************************************************************************/

uint32_t GetMBAddr(uint32_t mb)

{

//根据payload有效载荷大小来计算出每个MB的地址长度，因为这个版本的库没有封装MB寄存器

//检查的MBDSR0位的有效载荷大小，这个位描述的是block 0 的有效载荷，如果要知道其他 block 的 MB就需要修改与的位，以及下方RAMn的积地址（修改RAMn是个人理解，还未实践过）

uint8_t payload_size = 1UL << (((CAN_0.FDCTRL.R & 0x30000U) >> 16U) + 3U); // R & 0x30000U get payload size for memory block 0

//根据上面的小算法按照有效载荷大小来计算MB地址长度，根据地址长度在基地址上进行偏移得到想要的MB寄存器的地址

//CAN_0.RAMn是每个元素占用4字节，384/96 = 4 ，定义的这个数组空间实际表示的是MB一共占用的内存大小

return ((uint32_t)&CAN_0.RAMn[0].R + (8+payload_size)*mb);

/* 如果要知道其他 block 下的 MB 地址，则需要根据 */

}

/*******************************************************************************

Function Name : TransmitMsgFD

Engineer : Petr Stancik

Date : Jun-22-2021

Parameters : mb ... mb number used

ext ... 0-standard ID, 1-extended ID

ID ... ID to be sent

length ... number of bytes to be sent

Modifies : NONE

Returns : NONE

Notes : Transmit message once using selected MB

Issues : NONE

*******************************************************************************/

void TransmitMsgFD(uint32_t mb, uint8_t ext, uint32_t ID, uint8_t length)

{

/* Assumption: Message buffer CODE is INACTIVE */

uint8_t i,dlc,z=0;

uint32_t *pTxMB = GetMBAddr(mb);

uint32_t txID = (ext==0) ? ID<<18 : ID;

/*calculate dlc value from no. bytes*/

if(length < 0x09)

{

dlc = length;

}else if(length < 0x0D){

dlc = 0x9;

}else if(length < 0x11){

dlc = 0xA;

}else if(length < 0x15){

dlc = 0xB;

}else if(length < 0x19){

dlc = 0xC;

}else if(length < 0x21){

dlc = 0xD;

}else if(length < 0x31){

dlc = 0xE;

}else{

dlc = 0xF;

}

*(pTxMB + 1) = txID; // write ID

for (i=0; i<length/4; i++,z+=4) {

*(pTxMB + 2 + i) = z<<24 | (z+1)<<16 | (z+2)<< 8 | z+3; /* Data to be transmitted */

}

*pTxMB = (0 // Tx Buffer 0 T0 word

| 1<<31 // extended Data Length

| 1<<30 // bit rate switch

| 0xC<<24 // code = 0xC, TX once

| 1<<22 // SRR = 1

| ext<<21 // IDE

| 0<<20 // RTR = 0

| dlc<<16); // DLC

while (!(CAN_0.IFLAG1.R & 1<<mb)) {}; /* Wait for CAN 0 MB 0 flag */

CAN_0.IFLAG1.R = 1<<mb; // clear MB flag

}

我个人理解的是，我将block0配置payload为64字节，因此只能使用0~6的MB，为了能使用block1，我将设置CAN_0.FDCTRL.R = 0x80180000; 是block1也为64字节有效载荷，除了更改这一部分还更改的部分有GetMBAddr中payload_size = 1UL << (((CAN_0.FDCTRL.R & 0x180000U) >> 16U) + 3U);使其能获得MB7~13的地址，但是我这么修改我无法发送出数据，程序会一直卡在while (!(CAN_0.IFLAG1.R & 1<<mb)) {};不知道是什么原因，我认为问题是出在GetMBAddr函数获取MB地址这一部分，对于这一部分我理解的不是很透彻，不知道要如何进行修改才能获取block1下MB的地址，使block1也能发送canfd数据

S32GのトピックMPC 5748 CANFD

MPC 5748 CANFD