NUCLEO-F103RB - CAN bus problem - No TX sent

[jacopo]

Posted on March 20, 2015 at 02:50

Greetings,

I am currently testing the bxCAN integrated in the STM32F103RBT6 available on the Nucleo I'm using (F103RB). Up until now I used an example which should be able to transmit correctly a message, and also to receive them from an external source provided the presence of a CAN transceiver. But the problem is that, even by checking by using an oscilloscope, CAN_TX does not transfer what I want. Here is the following code. I'm using the CAN1 peripheral, remapped on the PB8 and PB9 pins of the microcontroller.

#include <stm32f10x.h>

#define LED_pin 5

/* GPIO CAN: PD0 E PD1 */

CAN_InitTypeDef CAN_InitStructure;

CAN_FilterInitTypeDef CAN_FilterInitStructure; GPIO_InitTypeDef GPIO_InitStructure, LED_InitStructure; NVIC_InitTypeDef NVIC_InitStructure;

uint32_t i;

CanTxMsg TxMessage;

CanRxMsg RxMessage; uint8_t TransmitMailbox = 0;

void

clock_init( void ) { /*Configure all clocks to max for best performance. * If there are EMI, power, or noise problems, try slowing the clocks*/

/* First set the flash latency to work with our clock*/

/*000 Zero wait state, if 0 MHz < SYSCLK <= 24 MHz 001 One wait state, if 24 MHz < SYSCLK <= 48 MHz 010 Two wait states, if 48 MHz < SYSCLK <= 72 MHz */ FLASH_SetLatency(FLASH_Latency_1);

/* Start with HSI clock (internal 8mhz), divide by 2 and multiply by 9 to

* get maximum allowed frequency: 36Mhz * Enable PLL, wait till it's stable, then select it as system clock*/ RCC_PLLConfig(RCC_PLLSource_HSI_Div2, RCC_PLLMul_9); RCC_PLLCmd(ENABLE); while (RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET); RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

/* Set HCLK, PCLK1, and PCLK2 to SCLK (these are default */

RCC_HCLKConfig(RCC_SYSCLK_Div1); RCC_PCLK1Config(RCC_HCLK_Div1); RCC_PCLK2Config(RCC_HCLK_Div1);

/* Set ADC clk to 9MHz (14MHz max, 18MHz default)*/

RCC_ADCCLKConfig(RCC_PCLK2_Div4);

/*To save power, use below functions to stop the clock to ceratin

* peripherals * RCC_PeriphClockCmd */

}

void

LED_init( void ) { RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); LED_InitStructure.GPIO_Pin = GPIO_Pin_5; LED_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; LED_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; GPIO_Init(GPIOA, &LED_InitStructure);

}

void

CAN_TX() { TxMessage.StdId=0x11; TxMessage.RTR=CAN_RTR_DATA; TxMessage.IDE=CAN_ID_STD; TxMessage.DLC=2; TxMessage.Data[0]=0xCA; TxMessage.Data[1]=0xFE;

TransmitMailbox=CAN_Transmit(CAN1, &TxMessage);

i = 0; while ((CAN_TransmitStatus(CAN1, TransmitMailbox) != CAN_TxStatus_Ok) && (i != 0xFFFF)) { i++; }

i = 0;

while ((CAN_MessagePending(CAN1, CAN_FIFO0) < 1) && (i != 0xFFFF)) { i++; }

RxMessage.StdId=0x00;

RxMessage.IDE=CAN_ID_STD; RxMessage.DLC=0; RxMessage.Data[0]=0x00; RxMessage.Data[1]=0x00; CAN_Receive(CAN1, CAN_FIFO0, &RxMessage); }

void

CAN_init( void ) {

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE); RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);

/* Configure CAN pins: CAN_TX and CAN_RX */

/* CAN RX */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; GPIO_Init(GPIOB, &GPIO_InitStructure);

/* CAN TX */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_Init(GPIOB, &GPIO_InitStructure);

GPIO_PinRemapConfig(GPIO_Remap1_CAN1,ENABLE);

// /* Enable CAN reset state */

// RCC_APB1PeriphResetCmd(RCC_APB1Periph_CAN1, ENABLE); // /* Release CAN from reset state */ // RCC_APB1PeriphResetCmd(RCC_APB1Periph_CAN1, DISABLE);

NVIC_InitStructure.NVIC_IRQChannel = USB_LP_CAN1_RX0_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = DISABLE;; NVIC_Init(&NVIC_InitStructure);

CAN_DeInit(CAN1);

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 = ENABLE; CAN_InitStructure.CAN_RFLM = DISABLE; CAN_InitStructure.CAN_TXFP = DISABLE; CAN_InitStructure.CAN_Mode = CAN_Mode_LoopBack; CAN_InitStructure.CAN_SJW = CAN_SJW_1tq; CAN_InitStructure.CAN_BS1 = CAN_BS1_12tq; CAN_InitStructure.CAN_BS2 = CAN_BS2_5tq; CAN_InitStructure.CAN_Prescaler = 1;

// 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=DISABLE;

CAN_Init(CAN1, &CAN_InitStructure);

// CAN_FilterInit(&CAN_FilterInitStructure); CAN_ITConfig(CAN1, CAN_IT_FMP0, ENABLE);

}

void

main ( void ) { clock_init(); LED_init(); CAN_init(); CAN_TX(); while (1); }

void

USB_LP_CAN1_RX0_IRQHandler( void ) { if (CAN_GetITStatus(CAN1, CAN_IT_FMP0) != RESET) CAN_Receive(CAN1, CAN_FIFO0, &RxMessage); CAN_ClearITPendingBit(CAN1, CAN_IT_FMP0); }

void

assert_failed(u8* file, u32 line) { /* User can add his own implementation to report the file name and line number, ex: printf(''Wrong parameters value: file %s on line %d\r\n'', file, line) */ /* Infinite loop */ while (1) { for (i=0;i<100000;i++); } }

[Tesla DeLorean]

Posted on March 20, 2015 at 12:46

Try it without Loopback to another node.

[jacopo]

Posted on March 20, 2015 at 14:50

Hi clive1,

yes I already did that. I forgot to change the mode since I did some other tests. By removing the loopback mode (which by the way does not work either) I still get nothing in output on pin PB9, which is the remapping pin for CAN1_TX I've chosen.