Transmit message ids on stm32f407 board in CAN Communication

[rohitkumarkv07]

I have tried to transmit message through stm32f407 and want to see the signals. But I am not able to see that in logic analyzer. Can you help me out.

#include "Mcu.h"
#include "stm32f4xx.h"
#include "Mcu_RegTypes.h"
#include "Mcu_InternalTypes.h"

void CAN1_Init(void);
void CAN1_Tx(uint8_t tr);
uint8_t CAN1_Rx(void);
void TIM4_ms_Delay(uint32_t delay);
uint8_t k = 0;
uint8_t rec = 0;


void GPIO_Init(){
	// Enable GPIOB clock signal
	//RCC->AHB1ENR |= RCC_AHB1ENR_GPIODEN;

	// Configuring PD0 and PD1 in alternate function mode
	GPIOD->MODER |= GPIO_MODER_MODE1_1  | GPIO_MODER_MODE0_1 ;

	// Selecting AF9 for PD0 and PD1 (See Page 272 of dm00031020)
	GPIOD->AFR[1] |= (GPIO_AFRL_AFSEL0_3 | GPIO_AFRL_AFSEL0_1 | GPIO_AFRL_AFSEL1_0 | GPIO_AFRL_AFSEL1_3);
}

void CAN1_Init(){
	/* 1. Setting Up the Baud Rate and Configuring CAN1 in*/

	// Enable clock for CAN1
	RCC->APB1ENR |= RCC_APB1ENR_CAN1EN;

	// Entering CAN Initialization Mode and wait for acknowledgment
	CAN1->MCR |= CAN_MCR_INRQ;
	while (!(CAN1->MSR & CAN_MSR_INAK)){}

	//Set Loop back mode for CAN1
	CAN1->BTR &= ~CAN_BTR_LBKM;

	//Setting the Re synchronization jump width to 1
	CAN1->BTR &= ~CAN_BTR_SJW;

	//Setting the no. of time quanta for Time segment 2
	// TS2 = 4-1;
	CAN1->BTR &= ~(CAN_BTR_TS2);
	CAN1->BTR |= (CAN_BTR_TS2_1 | CAN_BTR_TS2_0);

	//Setting the no. of time quanta for Time segment 1
	// TS1 = 3-1;
	CAN1->BTR &= ~(CAN_BTR_TS1);
	CAN1->BTR |= (CAN_BTR_TS1_1);

	//Setting the Baud rate Pre-scalar for CAN1
	// BRP[9:0] = 16-1
	CAN1->BTR |= ((16-1)<<0);

	// Exit the Initialization mode for CAN1
	// Wait until the INAK bit is cleared by hardware
	CAN1->MCR &= ~CAN_MCR_INRQ;
	while (CAN1->MSR & CAN_MSR_INAK){}

	//Exit Sleep Mode
	CAN1->MCR &= ~ CAN_MCR_SLEEP;
	//while (CAN1->MSR & CAN_MSR_SLAK);

	/* 2. Setting up the Transmission----------------------------------------*/

	CAN1->sTxMailBox[0].TIR = 0;

	//Setting up the Std. ID

	CAN1->sTxMailBox[0].TIR = (0x01 << 21);


	CAN1->sTxMailBox[0].TDHR = 0;

	// Setting Data Length to 1 Byte.
	CAN1->sTxMailBox[0].TDTR = 1;

	/* 3. Configuring the Filters--------------------------------------------*/

	//Enter Filter Initialization mode to configure the filters
	CAN1->FMR |= CAN_FMR_FINIT;

	// Configuring the Number of Filters Reserved for CAN1
	// and also the start bank for CAN2
	CAN1->FMR |= 14<<8;


	// Select the single 32-bit scale configuration
	CAN1->FS1R |= CAN_FS1R_FSC13;

	// Set the receive ID
	//CAN1->sFilterRegister[13].FR1 = 0x0; // Accept any message ID
	CAN1->sFilterRegister[0].FR1 = (0x01 << 21);

	// Select Identifier List mode
	CAN1->FM1R &= ~CAN_FM1R_FBM13; // Use mask mode

	//Activating filter 13
	//CAN1->FA1R |= CAN_FA1R_FACT13;
	CAN1->FA1R |= (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3);

	//Exit filter Initialization Mode
	CAN1->FMR &= ~CAN_FMR_FINIT;
}

void CAN1_Tx(uint8_t tr){
	// Put the Data to be transmitted into Mailbox Data Low Register
	CAN1->sTxMailBox[0].TDLR = tr;

	// Request for Transmission
	CAN1->sTxMailBox[0].TIR |= 1;

}

uint8_t CAN1_Rx(){
	// Monitoring FIFO 0 message pending bits FMP0[1:0]
	//while(!(CAN1->RF0R & 3)){}

	// Read the message ID from the FIFO 0 mailbox
	uint32_t RIR = CAN1->sFIFOMailBox[0].RIR;
	uint8_t RxD = (CAN1->sFIFOMailBox[0].RDLR) & 0xFF;

	// Extract message ID from RIR
	uint32_t msgID = RIR >> 21;

	// Releasing FIFO 0 output mailbox
	CAN1->RF0R |= 1 << 5;

	return msgID;
}


int main()
{
	
	Mcu_Init(&Mcu_ConfigSet[0]);
	Mcu_InitClock(0);
	while (MCU_PLL_LOCKED != Mcu_GetPllStatus());
	Mcu_DistributePllClock();
	GPIO_Init();
	CAN1_Init();




	while (1)
	{

		// Main program loop
		CAN1_Tx(k);
		rec = CAN1_Rx();
		k += 1;
		if (k > 25)
			k = 0;
	}
}

[SofLit]

Hello,

You need to configure GPIOs even in loopback mode + Rx pin set at pull-up but you disabled the RCC clock for GPIOB!

PS: again: please start with a HAL example to at least validate the HW and inspire from it for your register level programming.