STM32F103RB CAN PINS PROBLEM

Posted on April 11, 2013 at 16:03

Hi,

I have a problem with the CAN keil example for mcbstm32 board.

I use this example a lot with the remap for CAN so the pins are PB8 and PB9. That is theDefault configuration for the board.

I tried to change the pins to original position with no remap (PA11 and PA12) to test the program with another board.

So I go to CAN_STM32Fc and change the function to:

/* 1. Enable CAN controller Clock */

RCC->APB1ENR |= (1 <<

25

);

/* Note: MCBSTM32 uses PB8 and PB9 for CAN */

/* 2. Setup CAN Tx and Rx pins */

// RCC->APB2ENR |= (1 <<

0

); // enable clock for Alternate Function

// AFIO->MAPR &= 0xFFFF9FFF; // reset CAN remap

// AFIO->MAPR |= 0x00004000; // set CAN remap, use PB8, PB9

/* GPIOB clock enable */

// RCC->APB2ENR |= (1 <<

3

);

/* Configure CAN pin: RX PB.8 input push pull */

// GPIOB->CRH &= ~(0x0F<<

0

);

// GPIOB->CRH |= (0x08<<

0

);

/* Configure CAN pin: TX PB.9 alternate output push pull */

// GPIOB->CRH &= ~(0x0F<<

4

);

// GPIOB->CRH |= (0x0B<<

4

);

/* 2. Setup CAN Tx and Rx pins */

/* GPIOA clock enable */

RCC->APB2ENR |= (1 <<

2

);

/* Configure CAN pin: RX PA.11 input push pull */

GPIOA->CRH &= ~(0x0F<<

12

);

GPIOA->CRH |= (0x08<<

12

);

/* Configure CAN pin: TX PA.12 alternate output push pull */

GPIOA->CRH &= ~(0x0F<<

16

);

GPIOA->CRH |= (0x0B<<

16

);

/* 3. Setup IRQ vector for CAN interrupt */

/* not necessary */

/* 4. Enable CAN interrupt */

NVIC->IPR [4] |= 0x10000000; /* set priority lower than SVC */

NVIC->ISER[0] |= (1 << (USB_HP_CAN_TX_IRQChannel & 0x1F));

/* only FIFO 0 is used */

NVIC->IPR [5] |= 0x00000010; /* set priority lower than SVC */

NVIC->ISER[0] |= (1 << (USB_LP_CAN_RX0_IRQChannel & 0x1F));

return CAN_OK;

It compile ok but after callingCAN_Start it stucks.

The example is: C:\Keil\ARM\Boards\Keil\MCBSTM32\RL\CAN

Any ideas?

Thanks