Zoltan Hudak / CANnucleo

Controller Area Network library for NUCLEO boards equipped with CAN peripheral.

Dependents:   Nucleo-Courtois CANBLE CANnucleo_Hello3 Nucleo_Serialprintf ... more

Controller Area Network library for the NUCLEO and DISCOVERY boards equipped with CAN peripheral

Provides CAN support for the following boards:

• NUCLEO-F072RB
• NUCLEO-F091RC
• NUCLEO-F103RB
• NUCLEO-F302R8
• NUCLEO-F303RE
• NUCLEO-F303K8
• NUCLEO-F334R8
• DISCO-F334C8
• NUCLEO-F446RE
• STM32F103C8T6
• Maple Mini

with the following features:

• Easy to use. Delete the mbed library from your project and import the latest mbed-dev and CANnucleo libraries. In the mbed-dev library open the device.h file associated with the selected target board and add #undef DEVICE_CAN as follows:
  

#ifndef MBED_DEVICE_H
#define MBED_DEVICE_H

//=======================================
#define DEVICE_ID_LENGTH       24

#undef DEVICE_CAN

#include "objects.h"

#endif

See the CANnucleo_Hello demo for more details.

• Automatic recovery from bus-off state can be enabled/disabled in the constructor (defaults to ENABLE).
• Up to 14 filters (0 - 13) are available for the application to set up for message filtering performed by hardware.
  For more details see below or have a look at the comments in CANnucleo.cpp.
• One CAN channel per NUCLEO board is supported. The CAN peripheral can be connected either to pins PA_11, PA_12 (Receiver, Transmitter) or to pins PB_8, PB_9 (Receiver, Transmitter). This is configured when creating a CAN instance.
• Simplifies adding/getting data to/from a CAN message by using the << (append) and the >> (extract) operators.

Filtering performed by the built-in CAN controller without disturbing the CPU

CANnucleo supports only mask mode and 32-bit filter scale. Identifier list mode filtering and 16-bit filter scale are not supported. There are 14 filters available (0 - 13) for the application to set up. Each filter is a 32-bit filter defined by a filter ID and a filter mask. If no filter is set up then no CAN message is accepted! That's why filter #0 is set up in the constructor to accept all CAN messages by default. On reception of a message it is compared with filter #0. If there is a match, the message is accepted and stored. If there is no match, the incoming identifier is then compared with the next filter. If the received identifier does not match any of the identifiers configured in the filters, the message is discarded by hardware without disturbing the software.

CAN filter function - designed to setup a CAN filter

int CAN::filter(unsigned int id, unsigned int mask, CANFormat format, int handle)

Parameters

id - 'Filter ID' defines the bit values to be compared with the corresponding received bits.

Mapping of 32-bits (4-bytes) :

• STID - Stardard Identifier bits
• EXID - Extended Identifier bits
• [x:y]- bit range
• IDE - Identifier Extension bit (0 -> Standard Identifier, 1 -> Extended Identifier)
• RTR - Remote Transmission Request bit (0 -> Remote Transmission Request, 1 -> Standard message)

mask - 'Filter mask' defines which bits of the 'Filter ID' are compared with the received bits and which are disregarded.
Mapping of 32-bits (4-bytes) :

• STID - Stardard Identifier bits
• EXID - Extended Identifier bits
• [x:y]- bit range
• IDE - Identifier Extension bit
• RTR - Remote Transmission Request bit

• 1 -> bit is considered
• 0 -> bit is disregarded

format - This parameter must be CANAny
handle - Selects the filter. This parameter must be a number between 0 and 13.
retval - 0 - successful, 1 - error, 2 - busy, 3 - time out

Example of filter set up and filtering

Let's assume we would like to accept only messages with standard identifier 0x207:

STID[15:0] = 0x207 = 00000010 00000111

We map the STID to filter ID by shifting the bits adequately:

Filter ID = STID << (16 + (15 - 10)) = STID << 21 = 01000000 11100000 00000000 00000000

To compare only the bits representing STID we set the filter mask appropriately:

Filter mask = 11111111 11100000 00000000 00000100 = 0xFFE00004
              |||||||| |||                    |
              -------- ---                    |
                  |     |                     |
           STID[10:3]  STID[2:0]             IDE

Recall that filter #0 has been set up in the constructor to accept all CAN messages by default. So we have to reconfigure it. If we were set up filter #1 here then filter #0 would accept all the messages and no message would reach filter #1!
To reconfigure (set up) filter #0 we call:

can.filter(0x207 << 21, 0xFFE00004, CANAny, 0);

            Only these bits of 'Filter id' (set to 1 here in 'Filter mask') are compared 
            with the corresponding bits of received message (the others are disregarded)
                                |
                 ---------------------------------
                 |||||||| |||                    |
   Filter mask = 11111111 11100000 00000000 00000100 (= 0xFFE00004)
   Filter id   = 01000000 11100000 00000000 00000000 (= 0x40E00000)
                 |||||||| |||                    |
                 ---------------------------------
                                |
            To accept the message the values of these bits must match.
            Otherwise the message is passed to the next filter or
            discarded if this was the last active filter.
                                |
                 ---------------------------------
                 |||||||| |||                    |
   Received id = 01000000 11100000 00000000 00000010 (= 0x40E00002)
                             ||||| |||||||| ||||| ||
                             -----------------------
                                         |
                          These bits (set to 0 in 'Filter mask') are disregarded (masked).
                          They can have arbitrary values.

NOTE: For the meaning of individual bits see the mapping of 32-bits explained above.

We can use the filter function to setup more (up to 14) CAN filters for example as follows:

can.filter(0x207 << 21, 0xFFE00004, CANAny, 0);    // filter #0
can.filter(0x251 << 21, 0xFFE00004, CANAny, 1);    // filter #1
can.filter(0x304 << 21, 0xFFE00004, CANAny, 2);    // filter #2
...

 /**
 ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT(c) 2014 STMicroelectronics</center></h2>
  *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
  *   1. Redistributions of source code must retain the above copyright notice,
  *      this list of conditions and the following disclaimer.
  *   2. Redistributions in binary form must reproduce the above copyright notice,
  *      this list of conditions and the following disclaimer in the documentation
  *      and/or other materials provided with the distribution.
  *   3. Neither the name of STMicroelectronics nor the names of its contributors
  *      may be used to endorse or promote products derived from this software
  *      without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************
  *
  * Modified by Zoltan Hudak    <hudakz@inbox.com>
  *
  ******************************************************************************
  */

#ifndef stm32f4xx_hal_H
#define stm32f4xx_hal_H

#define CAN_IRQ  CAN1_RX0_IRQn

#include "pinmap.h"

typedef struct can_s    can_t;

#ifdef __cplusplus
extern "C"
{
#endif

/**
  * @brief  CAN initialization.
  * @param  obj: can_t object
  * @param  rxPin: RX pin name
  * @param  txPin: TX pin name
  * @param  abom: Automatic recovery from bus-off state
  * @retval None
  */
void initCAN(can_t* obj, PinName rxPin, PinName txPin, FunctionalState abom);

/**
  * @brief  CAN MSP Initialization
  * @param  hcan: CAN handle pointer
  * @retval None
  */
void HAL_CAN_MspInit(CAN_HandleTypeDef* hcan);

/**
  * @brief CAN MSP De-Initialization
  *        This function frees the hardware resources used:
  *          - Disable the Peripheral's clock
  *          - Revert GPIO to their default state
  * @param hcan: CAN handle pointer
  * @retval None
  */
void HAL_CAN_MspDeInit(CAN_HandleTypeDef* hcan);

/**
* @brief  Handles CAN1 RX0 interrupt request.
* @param  None
* @retval None
*/
void USB_LP_CAN_RX0_IRQHandler(void);

/**
  * @brief  Transmission  complete callback in non blocking mode
  * @param  _canHandle: pointer to a CAN_HandleTypeDef structure that contains
  *         the configuration information for the specified CAN.
  * @retval None
  */
void HAL_CAN_RxCpltCallback(CAN_HandleTypeDef* _canHandle);

#ifdef __cplusplus
}

#endif

#endif