[ECOS] CAN on STM32 - No transmitting

[Bernhard Gebert <bernhard_gebert at web dot de>]

Hello,

working with eCos 3.0 on STM32F103 single chip, my next problem is 
CAN-related.

To keep the beginning as simple as possible, I decided to write an 
example without eCos to test my hardware (and maybe my basic knowledge :-)).
I built an example with GCC (C++) running on my hardware without any 
problems, now I want to port it to eCos. It uses an older version of the 
ST peripheral lib.
I want to access the CAN-bus without a driver but directly from my 
example app.

Now my problem:
Polling telegrams is possible from FIFO0, but when I enqueue a Telegram, 
it never gets sent; after writing all three send buffers, the chip goes 
bus-off.
Using an oscilloscope, i found out there is nothing at the output pins.
As I am able to receive correctly, and the same hw with the same code 
can transmit, it might be a small bug.

Can you help me?

Brg,
Bernhard


The basic code:

void RCC_Configuration()
{
   /* HCLK = SYSCLK */
   RCC_HCLKConfig(RCC_SYSCLK_Div1);

   /* PCLK2 = HCLK */
   RCC_PCLK2Config(RCC_HCLK_Div1);

   /* PCLK1 = HCLK/2 */
   RCC_PCLK1Config(RCC_HCLK_Div2);

   /* Enable PLL */
   RCC_PLLCmd(ENABLE);

 /* GPIO clock enable */
 RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO |RCC_APB2Periph_GPIOD, 
ENABLE); // CAN is D.0 and D.1

 /* CAN1 Periph clock enable */
 RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN, ENABLE);
}

void GPIO_Configuration(void)
{
   #define GPIO_Remap2_CAN1            ((unsigned int)0x001D6000)
   #define RCC_APB2Periph_GPIO_CAN    RCC_APB2Periph_GPIOD
   #define GPIO_Remap_CAN             GPIO_Remap2_CAN1
   #define GPIO_CAN                   GPIOD
   #define GPIO_Pin_CAN_RX            GPIO_Pin_0
   #define GPIO_Pin_CAN_TX            GPIO_Pin_1

   GPIO_InitTypeDef  GPIO_InitStructure;

 /* Configure CAN pin: RX */
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_CAN_RX;
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
 GPIO_Init(GPIO_CAN, &GPIO_InitStructure);

 /* Configure CAN pin: TX */
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_CAN_TX;
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
 GPIO_Init(GPIO_CAN, &GPIO_InitStructure);

 GPIO_PinRemapConfig(GPIO_Remap_CAN , ENABLE);
}

void CAN_Config(void)
{
   CAN_InitTypeDef        CAN_InitStructure;
   CAN_FilterInitTypeDef  CAN_FilterInitStructure;

   /* CAN register init */
   CAN_DeInit();
   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_InitStructure.CAN_BS1 = CAN_BS1_3tq;
   CAN_InitStructure.CAN_BS2 = CAN_BS2_5tq;
   CAN_InitStructure.CAN_Prescaler = 16;//should result in ~250 kB
   if(CAN_Init(&CAN_InitStructure) != CANINITOK)
   {
       diag_printf("CAN_Config() failed!\r\n");
   }
   else
   {
       diag_printf("CAN_Config() succeeded.\r\n");
   }

   /* 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);
}

void CCanPort::Init (void)
{
   static int i = 0;
       RCC_Configuration();
       GPIO_Configuration();
       CAN_Config();

...
       CAN_Receive(CAN_FIFO0, &RxMessage);
       CAN_Transmit(&TxMessage) ;

}




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