I can't see any signal on the CAN_TX line - c

Question

I try to use the CAN bus on an STM32F303 discovery board, and I am using the PD0→RX and PD1→TX pins.
I want to try to send a message and analyse on the oscilloscope. So my configuration is seen below in the code blocks.
When I analyse with the oscilloscope which pins are PD0 and PD1, I can't see anything on the oscilloscope.
Where is my fault?
This is my code:
#include <stm32f30x.h>
#include <stm32f30x_i2c.h>
#include <stm32f30x_rcc.h>
#include <stm32f30x_syscfg.h>
#include <stm32f30x_exti.h>
// #include <stm32f30x_misc.h>
#include "main.h"
#include <stdio.h>
#include "common.h"
#include "io_periph_defs.h"
#include "stm32f30x.h"
#include <stdio.h>
#include "conf.h"
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
CAN_InitTypeDef CAN_InitStructure;
CAN_FilterInitTypeDef CAN_FilterInitStructure;
CAN_InitTypeDef CAN_InitStructure;
CAN_FilterInitTypeDef CAN_FilterInitStructure;
CanTxMsg TxMessage;
CanRxMsg RxMessage;
void Init_TxMes(CanTxMsg *TxMessage)
{
/* Transmit INITIALIZATION*/
TxMessage->IDE = CAN_ID_STD;
TxMessage->DLC = 2;
TxMessage->StdId = 0x321;
TxMessage->RTR = CAN_RTR_DATA;
}
void Init_RxMes(CanRxMsg *RxMessage)
{
uint8_t i = 0;
RxMessage->StdId = 0;
RxMessage->IDE = CAN_ID_STD;
RxMessage->DLC = 0;
RxMessage->FMI = 0;
for (i = 0; i < 8; i++)
{
RxMessage->Data[i] = 0;
}
}
void CAN_setup(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE); //Enable the clock for CAN
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOD, ENABLE);
/* Configure CAN1 RX pin */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOD, &GPIO_InitStructure);
/* Configure CAN1 TX pin */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOD, &GPIO_InitStructure);
GPIO_PinAFConfig(GPIOD, GPIO_PinSource0, GPIO_AF_9);
GPIO_PinAFConfig(GPIOD, GPIO_PinSource1, GPIO_AF_9);
/* Enable the CAN global Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = CAN1_SCE_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
NVIC_InitStructure.NVIC_IRQChannel = CAN1_RX1_IRQn;
NVIC_Init(&NVIC_InitStructure);
CAN_DeInit(CAN1);
/* Configure CAN1 **************************************************/
/* Struct init*/
CAN_StructInit(&CAN_InitStructure);
/* CAN cell init */
CAN_InitStructure.CAN_TTCM = DISABLE;
CAN_InitStructure.CAN_ABOM = DISABLE;
CAN_InitStructure.CAN_AWUM = DISABLE;
CAN_InitStructure.CAN_NART = DISABLE;
CAN_InitStructure.CAN_RFLM = DISABLE;
CAN_InitStructure.CAN_TXFP = DISABLE;
CAN_InitStructure.CAN_Mode = CAN_Mode_Normal;
CAN_InitStructure.CAN_SJW = CAN_SJW_1tq;
/* CAN Baudrate = 125kbps (CAN clocked at 36 MHz) */
CAN_InitStructure.CAN_BS1 = CAN_BS1_9tq;
CAN_InitStructure.CAN_BS2 = CAN_BS2_8tq;
CAN_InitStructure.CAN_Prescaler = 16;
CAN_Init(CAN1, &CAN_InitStructure);
/* CAN filter init */
CAN_FilterInitStructure.CAN_FilterNumber = 0;
CAN_FilterInitStructure.CAN_FilterMode = CAN_FilterMode_IdMask;
CAN_FilterInitStructure.CAN_FilterScale = CAN_FilterScale_32bit;
CAN_FilterInitStructure.CAN_FilterIdHigh = 0x0000;
CAN_FilterInitStructure.CAN_FilterIdLow = 0x0000;
CAN_FilterInitStructure.CAN_FilterMaskIdHigh = 0x0000;
CAN_FilterInitStructure.CAN_FilterMaskIdLow = 0x0000;
CAN_FilterInitStructure.CAN_FilterFIFOAssignment = 0;
CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;
CAN_FilterInit(&CAN_FilterInitStructure);
}
int main(void)
{
int i;
uint8_t TransmitMailbox = 0;
CAN_setup(); // Set up CAN interface
Init_TxMes(&TxMessage);
init_pin(GPIOA, GPIO_Pin_8, GPIO_Mode_OUT, GPIO_Speed_50MHz, GPIO_OType_PP, GPIO_PuPd_UP);
while (1)
{
TxMessage.Data[0] = 0xAA;
GPIO_SetBits(GPIOA, GPIO_Pin_8); // Transmit data
TransmitMailbox = CAN_Transmit(CAN1, &TxMessage);
i = 0;
while ((CAN_TransmitStatus(CAN1, TransmitMailbox) != CANTXOK))
; // I put a breakpoint here to check
// and found the message is pending.
GPIO_ResetBits(GPIOA, GPIO_Pin_8); // Transmit data
//i++;
}
}
I think there is the problem, but how can I solve it?
Stacking in loop.
while ((CAN_TransmitStatus(CAN1, TransmitMailbox) != CANTXOK)