CAN2 on STM32F4-Discovery

[grant]

I believe the clock is a slave.

I was able to get the loopback mode working with this thread in the STM32 forums, but I'd rather be using ChibiOS

[Giovanni]

I am looking into this. I decided to remove filters from the configuration and implement a custom API for that (probably taking it from the FW library).

Giovanni

[Giovanni]

Hi,

Good news, it works

The STM32F4xx demo now activates both CANs. Could you make some testing on the driver? especially the new API that allows to setup the filters. Note that the filters setup must happen before calling canStart(). Now the configuration structure is simplified, filters are no more handled there.

Giovanni

[grant]

Giovanni, you are dedicated to your passion and it is clear that this is your passion. Thank you for your help!

I will absolutely test the filtering as it will most certainly be required in my anticipated application. I'll report my results as soon as I have a chance.

[Akronoz]

Hi, i search in the forum about CAN filters.

There is some API to configure the filters on the CAN bus? I found start, transmit, receive functions and examples, but I cant find some way to configure the filters like address filter for many MCU conected trough CAN.

Thanks Giovanni for your good work!

[Giovanni]

Hi,

CAN filters are mapped exactly as described in the reference manual of the STM32, you have to create an array of filters that the driver copies into the registers on initialization.

Giovanni

[Akronoz]

Hi, what function programs the filters, canStart?, I found inside can_lld this API

canSTM32SetFilters(uint32_t can2sb, uint32_t num, const CANFilter *cfp)

but seems that it set a filter in the bank filter but no specifies if the filter is in identifier mask mode or identifier list mode, how can I configure that?

Can post a very short example configuring one filter whit identifier list mode and setting up the first filter in the bank 0?

[Giovanni]

The filter modes are defined in the CANFilter structure:

Code: Select all

/**
 * @brief   CAN filter.
 * @note    Refer to the STM32 reference manual for info about filters.
 */
typedef struct {
  /**
   * @brief   Number of the filter to be programmed.
   */
  uint32_t                  filter;
  /**
   * @brief   Filter mode.
   * @note    This bit represent the CAN_FM1R register bit associated to this
   *          filter (0=mask mode, 1=list mode).
   */
  uint32_t                  mode:1;
  /**
   * @brief   Filter scale.
   * @note    This bit represent the CAN_FS1R register bit associated to this
   *          filter (0=16 bits mode, 1=32 bits mode).
   */
  uint32_t                  scale:1;
  /**
   * @brief   Filter mode.
   * @note    This bit represent the CAN_FFA1R register bit associated to this
   *          filter, must be set to zero in this version of the driver.
   */
  uint32_t                  assignment:1;
  /**
   * @brief   Filter register 1 (identifier).
   */
  uint32_t                  register1;
  /**
   * @brief   Filter register 2 (mask/identifier depending on mode=0/1).
   */
  uint32_t                  register2;
} CANFilter;

Giovanni

[Akronoz]

Thanks a lot!
I was looking for the structure in http://chibios.sourceforge.net/html/can ... ource.html and I saw there empty, because is specific for STM32F1.

Now I will try to config

[Akronoz]

Hi.
You say that the driver initialize the filters if I have an array, but I only found in the code that:

inside can_lld.c at the function can_lld_init:

Code: Select all

  /* Filters initialization.*/
#if STM32_HAS_CAN2
  can_lld_set_filters(STM32_CAN_MAX_FILTERS / 2, 0, NULL);
#else
  can_lld_set_filters(STM32_CAN_MAX_FILTERS, 0, NULL);
#endif

it is called by halInit, but the second parameter is 0 and in the code of the function i found:

Code: Select all

/**
 * @brief   Programs the filters.
 *
 * @param[in] can2sb    number of the first filter assigned to CAN2
 * @param[in] num       number of entries in the filters array, if zero then
 *                      a default filter is programmed
 * @param[in] cfp       pointer to the filters array, can be @p NULL if
 *                      (num == 0)
 *
 * @notapi
 */

for this reason the filter never takes my array, i think if i use the API canSTM32SetFilters, I will can program it, but the function is not visible from main.c, is there a problem? or I need to include can_lld.h at main?