CANopenNode drvTemplate/CO_driver.h hacking

/************************************************************************
 *            CANopenNode drvTemplate/CO_driver.h hacking
 * 说明：
 *     使用CANopenNode，drvTemplate/CO_driver.h说明了一些驱动编写相关的
 * 注意事项。
 *
 *                                    2017-3-24 深圳 南山平山村 曾剑锋
 ***********************************************************************/

/**
 * CAN module object for generic microcontroller.
 *
 * This file is a template for other microcontrollers.
 *
 * @file        CO_driver.h
 * @ingroup     CO_driver
 * @author      Janez Paternoster
 * @copyright   2004 - 2015 Janez Paternoster
 *
 * This file is part of CANopenNode, an opensource CANopen Stack.
 * Project home page is <https://github.com/CANopenNode/CANopenNode>.
 * For more information on CANopen see <http://www.can-cia.org/>.
 *
 * CANopenNode is free and open source software: you can redistribute
 * it and/or modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 * Following clarification and special exception to the GNU General Public
 * License is included to the distribution terms of CANopenNode:
 *
 * Linking this library statically or dynamically with other modules is
 * making a combined work based on this library. Thus, the terms and
 * conditions of the GNU General Public License cover the whole combination.
 *
 * As a special exception, the copyright holders of this library give
 * you permission to link this library with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also meet,
 * for each linked independent module, the terms and conditions of the
 * license of that module. An independent module is a module which is
 * not derived from or based on this library. If you modify this
 * library, you may extend this exception to your version of the
 * library, but you are not obliged to do so. If you do not wish
 * to do so, delete this exception statement from your version.
 */

#ifndef CO_DRIVER_H
#define CO_DRIVER_H

/* Include processor header file */
/**
 * 将这里的头文件替换成与处理器相关的头文件，譬如：
 *   1. STM32：
 *     #include "common.h"
 *     #include "stm32f10x_conf.h"
 *   2. SocketCAN：
 *      #include <stddef.h>         /* for 'NULL' */
 *      #include <stdint.h>         /* for 'int8_t' to 'uint64_t' */
 *      #include <stdbool.h>        /* for 'true', 'false' */
 *      #include <unistd.h>
 *      #include <endian.h>
 *
 *      #ifndef CO_SINGLE_THREAD
 *      #include <pthread.h>
 *      #endif
 *
 *      #include <linux/can.h>
 *      #include <linux/can/raw.h>
 *      #include <linux/can/error.h>
 */
#include <stddef.h>         /* for 'NULL' */
#include <stdint.h>         /* for 'int8_t' to 'uint64_t' */
#include <stdbool.h>        /* for 'true', 'false' */

/**
 * @defgroup CO_driver Driver
 * @ingroup CO_CANopen
 * @{
 *
 * Microcontroller specific code for CANopenNode.
 * 微控制器CANopenNode专用代码
 *
 * This file contains type definitions, functions and macros for:
 * 该文件包含为用于以下目的的类型定义，函数，宏
 *  - Basic data types.
 *    基础数据类型
 *  - Receive and transmit buffers for CANopen messages.
 *    CANopen信息发送和接收缓冲区
 *  - Interaction with CAN module on the microcontroller.
 *    在微控制器上和CAN模块进行交互
 *  - CAN receive and transmit interrupts.
 *    CAN信息接收和发送中断
 *
 * This file is not only a CAN driver. There are no classic CAN queues for CAN
 * messages. This file provides direct connection with other CANopen
 * objects. It tries to provide fast responses and tries to avoid unnecessary
 * calculations and memory consumptions.
 * 这份文件不仅仅是用于CAN驱动，这里没有典型的处理CAN消息的队列，通过直接连接其他的CANopen的对象，
 * 主要是为了提供最快的响应速度来避免不必要的计算和内存消耗
 *
 * CO_CANmodule_t contains an array of _Received message objects_ (of type
 * CO_CANrx_t) and an array of _Transmit message objects_ (of type CO_CANtx_t).
 * Each CANopen communication object owns one member in one of the arrays.
 * For example Heartbeat producer generates one CANopen transmitting object,
 * so it has reserved one member in CO_CANtx_t array.
 * SYNC module may produce sync or consume sync, so it has reserved one member
 * in CO_CANtx_t and one member in CO_CANrx_t array.
 * CO_CANmodule_t两个数组，一个是发送消息对象CO_CANrx_t，一个是接收信息的对象CO_CANtx_t，
 * 每一个CANopen通信对象在数组中拥有一个成员，例如：
 *   1. 心跳包生产者产生一个CANopen传输对象，所以他收到一个成员在CO_CANtx_t数组中。
 *   2. 同步模块可能会产生sync和消费sync，所以他保留了一个成员在CO_CANtx_t中，也
 *     保留一个在CO_CANrx_t中
 *
 * ###Reception of CAN messages.
 * Before CAN messages can be received, each member in CO_CANrx_t must be
 * initialized. CO_CANrxBufferInit() is called by CANopen module, which
 * uses specific member. For example @ref CO_HBconsumer uses multiple members
 * in CO_CANrx_t array. (It monitors multiple heartbeat messages from remote
 * nodes.) It must call CO_CANrxBufferInit() multiple times.
 * 在CAN消息被接收之前，每一个CO_CANrx_t需要先被初始化，CO_CANrxBufferInit被CANopen模块
 * 调用，有些特定的成员被使用，例如CO_HBconsumer使用了CO_CANrx_t多个成员，其监视远程节点
 * 上的多个心跳包，所以被CO_CANrxBufferInit()调用多次。
 *
 * Main arguments to the CO_CANrxBufferInit() function are CAN identifier
 * and a pointer to callback function. Those two arguments (and some others)
 * are copied to the member of the CO_CANrx_t array.
 * CO_CANrxBufferInit()主要参数是：
 *   1. CAN identifier；
 *   2. 回调的函数指针；
 * 这两个参数（也许包括其他的）都会被作为成员拷贝的CO_CANrx_t数组中。
 *
 * Callback function is a function, specified by specific CANopen module
 * (for example by @ref CO_HBconsumer). Each CANopen module defines own
 * callback function. Callback function will process the received CAN message.
 * It will copy the necessary data from CAN message to proper place. It may
 * also trigger additional task, which will further process the received message.
 * Callback function must be fast and must only make the necessary calculations
 * and copying.
 * 回调函数是一个函数，处理特定的CANopen模块相关数据，每一个CANopen模块定义了他们
 * 自己的回调函数，回调函数将处理接收到的CAN信息。他将从CAN信息中拷贝必要的数据到
 * 合适的地方，当然他也可以触发额外的任务，额外的任务会进一步处理接收到的信息。
 * 回调函数必须处理迅速，仅仅做那些必要的数据运算以及拷贝。
 *
 * Received CAN messages are processed by CAN receive interrupt function.
 * After CAN message is received, function first tries to find matching CAN
 * identifier from CO_CANrx_t array. If found, then a corresponding callback
 * function is called.
 * 接收CAN信息是由CAN接收中断函数进行处理的，在接收完数据之后，函数会尝试从CO_CANrx_t
 * 中去查找匹配的CAN identifier，如果被找到，那么正确的回调函数就会被调用。
 *
 * Callback function accepts two parameters:
 * 回调函数接收两个参数
 *  - object is pointer to object registered by CO_CANrxBufferInit().
 *    CO_CANrxBufferInit()中注册的对象指针
 *  - msg  is pointer to CAN message of type CO_CANrxMsg_t.
 *    CO_CANrxMsg_t类型的CAN信息指针
 *
 * Callback function must return #CO_ReturnError_t: CO_ERROR_NO,
 * CO_ERROR_RX_OVERFLOW, CO_ERROR_RX_PDO_OVERFLOW, CO_ERROR_RX_MSG_LENGTH or
 * CO_ERROR_RX_PDO_LENGTH.
 * 回调函数必须是返回如下CO_ReturnError_t类型的数据。
 *
 *
 * ###Transmission of CAN messages.
 * Before CAN messages can be transmitted, each member in CO_CANtx_t must be
 * initialized. CO_CANtxBufferInit() is called by CANopen module, which
 * uses specific member. For example Heartbeat producer must initialize it's
 * member in CO_CANtx_t array.
 * 在CAN消息被发送之前，CO_CANtx_t必须先被初始化，CO_CANtxBufferInit()被CANopen模块调用，
 * 会使用指定的成员，例如，心跳包产生者必须在CO_CANtx_t中初始化成员。
 *
 * CO_CANtxBufferInit() returns a pointer of type CO_CANtx_t, which contains buffer
 * where CAN message data can be written. CAN message is send with calling
 * CO_CANsend() function. If at that moment CAN transmit buffer inside
 * microcontroller's CAN module is free, message is copied directly to CAN module.
 * Otherwise CO_CANsend() function sets _bufferFull_ flag to true. Message will be
 * then sent by CAN TX interrupt as soon as CAN module is freed. Until message is
 * not copied to CAN module, its contents must not change. There may be multiple
 * _bufferFull_ flags in CO_CANtx_t array set to true. In that case messages with
 * lower index inside array will be sent first.
 * CO_CANtxBufferInit()返回CO_CANtx_t类型的指针，其中包含CAN信息可以被写入的数据缓冲区，
 * CAN信息通过CO_CANsend()函数进行发送，如果微处理器的CAN模块的CAN输出传输缓冲区被释放，
 * CAN信息将直接被拷贝进CAN模块中。
 * 另外CO_CANsend()函数设置_bufferFull_标志位true，消息将会被CAN模块尽快发送，在信息被
 * 拷贝到CAN模块之前，信息是不能被篡改的。因此，在CO_CANtx_t数组中，会有很多的_bufferFull_
 * 标志是true，在这种情况下，小的index会先被发送出去。
 */

/**
 * @name Critical sections
 * CANopenNode is designed to run in different threads, as described in README.
 * Threads are implemented differently in different systems. In microcontrollers
 * threads are interrupts with different priorities, for example.
 * It is necessary to protect sections, where different threads access to the
 * same resource. In simple systems interrupts or scheduler may be temporary
 * disabled between access to the shared resource. Otherwise mutexes or
 * semaphores can be used.
 * 如同在README中描述的，CANopenNode被设计于运行于不同的线程。
 * 线程在不同的系统中，实现的方式也是不同的，在微处理器中线程采用不同的优先级的中断来完成，例如
 * 像多个线程都要访问的部分是需要被保护的，在系统中这部分共享资源在访问的时候要关闭中断和任务调度，
 * 当然想互斥和信号量也是可以使用的。
 *
 * ####Reentrant functions.
 * Functions CO_CANsend() from C_driver.h, CO_errorReport() from CO_Emergency.h
 * and CO_errorReset() from CO_Emergency.h may be called from different threads.
 * Critical sections must be protected. Eather by disabling scheduler or
 * interrupts or by mutexes or semaphores.
 * 函数CO_CANsend()是在C_driver.h中的，CO_errorReport()/CO_errorReset()是在CO_Emergency.h中，
 * 他们都可能被任何线程调用，敏感的部分必须要被保护，需要采用禁止任务切换、中断，或者
 * 采用互斥、信号量来处理。
 *
 * ####Object Dictionary variables.
 * In general, there are two threads, which accesses OD variables: mainline and
 * timer. CANopenNode initialization and SDO server runs in mainline. PDOs runs
 * in faster timer thread. Processing of PDOs must not be interrupted by
 * mainline. Mainline thread must protect sections, which accesses the same OD
 * variables as timer thread. This care must also take the application. Note
 * that not all variables are allowed to be mapped to PDOs, so they may not need
 * to be protected. SDO server protects sections with access to OD variables.
 * 通常情况下，有两个线程会访问对象字典变量：主线程和定时器。CANopenNode初始化和SDO服务
 * 运行于主线程，PDOs运行于快速定时器线程，PDO的处理不能被mainline打断。因为对象字典
 * 能够同时被主线程、定时器访问，所以需要专门被保护，在引用层也是需要注意的。不过需要
 * 注意的是，并不是所有的PDO的对象都允许被映射，可能不需要被保护。
 *
 * ####CAN receive thread.
 * It partially processes received CAN data and puts them into appropriate
 * objects. Objects are later processed. It does not need protection of
 * critical sections. There is one circumstance, where CANrx should be disabled:
 * After presence of SYNC message on CANopen bus, CANrx should be temporary
 * disabled until all receive PDOs are processed. See also CO_SYNC.h file and
 * CO_SYNC_initCallback() function.
 * 专门处理CAN数据，并将其放到合适对象里，这些对象会被稍后处理，这是不需要被特殊处理的部分。
 * 这是一个事件，CANrx应该被关闭，在获取到SYNC的信息的时候，CANrx应该被短暂的关闭直到PDO信息
 * 被处理，请查看CO_SYNC.h文件和CO_SYNC_initCallback()函数
 * @{
 */
    #define CO_LOCK_CAN_SEND()  /**< Lock critical section in CO_CANsend() */
    #define CO_UNLOCK_CAN_SEND()/**< Unlock critical section in CO_CANsend() */

    #define CO_LOCK_EMCY()      /**< Lock critical section in CO_errorReport() or CO_errorReset() */
    #define CO_UNLOCK_EMCY()    /**< Unlock critical section in CO_errorReport() or CO_errorReset() */

    #define CO_LOCK_OD()        /**< Lock critical section when accessing Object Dictionary */
    #define CO_UNLOCK_OD()      /**< Unock critical section when accessing Object Dictionary */
/** @} */

/**
 * @defgroup CO_dataTypes Data types
 * @{
 *
 * According to Misra C
 */
    /* int8_t to uint64_t are defined in stdint.h */
    typedef unsigned char           bool_t;     /**< bool_t */
    typedef float                   float32_t;  /**< float32_t */
    typedef long double             float64_t;  /**< float64_t */
    typedef char                    char_t;     /**< char_t */
    typedef unsigned char           oChar_t;    /**< oChar_t */
    typedef unsigned char           domain_t;   /**< domain_t */
/** @} */

/**
 * Return values of some CANopen functions. If function was executed
 * successfully it returns 0 otherwise it returns <0.
 */
typedef enum{
    CO_ERROR_NO                 = ,    /**< Operation completed successfully */
    CO_ERROR_ILLEGAL_ARGUMENT   = -,   /**< Error in function arguments */
    CO_ERROR_OUT_OF_MEMORY      = -,   /**< Memory allocation failed */
    CO_ERROR_TIMEOUT            = -,   /**< Function timeout */
    CO_ERROR_ILLEGAL_BAUDRATE   = -,   /**< Illegal baudrate passed to function CO_CANmodule_init() */
    CO_ERROR_RX_OVERFLOW        = -,   /**< Previous message was not processed yet */
    CO_ERROR_RX_PDO_OVERFLOW    = -,   /**< previous PDO was not processed yet */
    CO_ERROR_RX_MSG_LENGTH      = -,   /**< Wrong receive message length */
    CO_ERROR_RX_PDO_LENGTH      = -,   /**< Wrong receive PDO length */
    CO_ERROR_TX_OVERFLOW        = -,   /**< Previous message is still waiting, buffer full */
    CO_ERROR_TX_PDO_WINDOW      = -,  /**< Synchronous TPDO is outside window */
    CO_ERROR_TX_UNCONFIGURED    = -,  /**< Transmit buffer was not confugured properly */
    CO_ERROR_PARAMETERS         = -,  /**< Error in function function parameters */
    CO_ERROR_DATA_CORRUPT       = -,  /**< Stored data are corrupt */
    CO_ERROR_CRC                = -   /**< CRC does not match */
}CO_ReturnError_t;

/**
 * CAN receive message structure as aligned in CAN module. It is different in
 * different microcontrollers. It usually contains other variables.
 */
typedef struct{
    /** CAN identifier. It must be read through CO_CANrxMsg_readIdent() function. */
    uint32_t            ident;
    uint8_t             DLC ;           /**< Length of CAN message */
    uint8_t             data[];        /**< 8 data bytes */
}CO_CANrxMsg_t;

/**
 * Received message object
 */
typedef struct{
    uint16_t            ident;          /**< Standard CAN Identifier (bits 0..10) + RTR (bit 11) */
    uint16_t            mask;           /**< Standard Identifier mask with same alignment as ident */
    void               *object;         /**< From CO_CANrxBufferInit() */
    void              (*pFunct)(void *object, const CO_CANrxMsg_t *message);  /**< From CO_CANrxBufferInit() */
}CO_CANrx_t;

/**
 * Transmit message object.
 */
typedef struct{
    uint32_t            ident;          /**< CAN identifier as aligned in CAN module */
    uint8_t             DLC ;           /**< Length of CAN message. (DLC may also be part of ident) */
    uint8_t             data[];        /**< 8 data bytes */
    volatile bool_t     bufferFull;     /**< True if previous message is still in buffer */
    /** Synchronous PDO messages has this flag set. It prevents them to be sent outside the synchronous window */
    volatile bool_t     syncFlag;
}CO_CANtx_t;

/**
 * CAN module object. It may be different in different microcontrollers.
 */
typedef struct{
    int32_t             CANbaseAddress; /**< From CO_CANmodule_init() */
    CO_CANrx_t         *rxArray;        /**< From CO_CANmodule_init() */
    uint16_t            rxSize;         /**< From CO_CANmodule_init() */
    CO_CANtx_t         *txArray;        /**< From CO_CANmodule_init() */
    uint16_t            txSize;         /**< From CO_CANmodule_init() */
    volatile bool_t     CANnormal;      /**< CAN module is in normal mode */
    /** Value different than zero indicates, that CAN module hardware filters
      * are used for CAN reception. If there is not enough hardware filters,
      * they won't be used. In this case will be *all* received CAN messages
      * processed by software. */
    volatile bool_t     useCANrxFilters;
    /** If flag is true, then message in transmitt buffer is synchronous PDO
      * message, which will be aborted, if CO_clearPendingSyncPDOs() function
      * will be called by application. This may be necessary if Synchronous
      * window time was expired. */
    volatile bool_t     bufferInhibitFlag;
    /** Equal to 1, when the first transmitted message (bootup message) is in CAN TX buffers */
    volatile bool_t     firstCANtxMessage;
    /** Number of messages in transmit buffer, which are waiting to be copied to the CAN module */
    volatile uint16_t   CANtxCount;
    uint32_t            errOld;         /**< Previous state of CAN errors */
    void               *em;             /**< Emergency object */
}CO_CANmodule_t;

/**
 * Endianes.
 * 大小端的问题
 *
 * Depending on processor or compiler architecture, one of the two macros must
 * be defined: CO_LITTLE_ENDIAN or CO_BIG_ENDIAN. CANopen itself is little endian.
 * 依赖于处理和编译器架构，这两个宏其中之一要被定义，cANopen本身是小端的。
 */
#define CO_LITTLE_ENDIAN

/**
 * Request CAN configuration (stopped) mode and *wait* untill it is set.
 * 请求CAN配置参数(停止)模式并直到被设置
 *
 * @param CANbaseAddress CAN module base address.
 */
void CO_CANsetConfigurationMode(int32_t CANbaseAddress);

/**
 * Request CAN normal (opearational) mode and *wait* untill it is set.
 * 请求cAN普通(操作)模式并直到被设置
 *
 * @param CANmodule This object.
 */
void CO_CANsetNormalMode(CO_CANmodule_t *CANmodule);

/**
 * Initialize CAN module object.
 * 初始化CAN模块对象
 *
 * Function must be called in the communication reset section. CAN module must
 * be in Configuration Mode before.
 *
 * @param CANmodule This object will be initialized.
 * @param CANbaseAddress CAN module base address.
 * @param rxArray Array for handling received CAN messages
 * @param rxSize Size of the above array. Must be equal to number of receiving CAN objects.
 * @param txArray Array for handling transmitting CAN messages
 * @param txSize Size of the above array. Must be equal to number of transmitting CAN objects.
 * @param CANbitRate Valid values are (in kbps): 10, 20, 50, 125, 250, 500, 800, 1000.
 * If value is illegal, bitrate defaults to 125.
 *
 * Return #CO_ReturnError_t: CO_ERROR_NO or CO_ERROR_ILLEGAL_ARGUMENT.
 */
CO_ReturnError_t CO_CANmodule_init(
        CO_CANmodule_t         *CANmodule,
        int32_t                 CANbaseAddress,
        CO_CANrx_t              rxArray[],
        uint16_t                rxSize,
        CO_CANtx_t              txArray[],
        uint16_t                txSize,
        uint16_t                CANbitRate);

/**
 * Switch off CANmodule. Call at program exit.
 * 关闭CAN模块，程序的最后需要被调用
 *
 * @param CANmodule CAN module object.
 */
void CO_CANmodule_disable(CO_CANmodule_t *CANmodule);

/**
 * Read CAN identifier from received message
 * 获取CAN identifier从接受到的信息中
 *
 * @param rxMsg Pointer to received message
 * @return 11-bit CAN standard identifier.
 */
uint16_t CO_CANrxMsg_readIdent(const CO_CANrxMsg_t *rxMsg);

/**
 * Configure CAN message receive buffer.
 * 配置CAN信息接收缓冲区
 *
 * Function configures specific CAN receive buffer. It sets CAN identifier
 * and connects buffer with specific object. Function must be called for each
 * member in _rxArray_ from CO_CANmodule_t.
 *
 * @param CANmodule This object.
 * @param index Index of the specific buffer in _rxArray_.
 * @param ident 11-bit standard CAN Identifier.
 * @param mask 11-bit mask for identifier. Most usually set to 0x7FF.
 * Received message (rcvMsg) will be accepted if the following
 * condition is true: (((rcvMsgId ^ ident) & mask) == 0).
 * @param rtr If true, 'Remote Transmit Request' messages will be accepted.
 * @param object CANopen object, to which buffer is connected. It will be used as
 * an argument to pFunct. Its type is (void), pFunct will change its
 * type back to the correct object type.
 * @param pFunct Pointer to function, which will be called, if received CAN
 * message matches the identifier. It must be fast function.
 *
 * Return #CO_ReturnError_t: CO_ERROR_NO CO_ERROR_ILLEGAL_ARGUMENT or
 * CO_ERROR_OUT_OF_MEMORY (not enough masks for configuration).
 */
CO_ReturnError_t CO_CANrxBufferInit(
        CO_CANmodule_t         *CANmodule,
        uint16_t                index,
        uint16_t                ident,
        uint16_t                mask,
        bool_t                  rtr,
        void                   *object,
        void                  (*pFunct)(void *object, const CO_CANrxMsg_t *message));

/**
 * Configure CAN message transmit buffer.
 * 配置CAN信息发送缓冲区
 *
 * Function configures specific CAN transmit buffer. Function must be called for
 * each member in _txArray_ from CO_CANmodule_t.
 *
 * @param CANmodule This object.
 * @param index Index of the specific buffer in _txArray_.
 * @param ident 11-bit standard CAN Identifier.
 * @param rtr If true, 'Remote Transmit Request' messages will be transmitted.
 * @param noOfBytes Length of CAN message in bytes (0 to 8 bytes).
 * @param syncFlag This flag bit is used for synchronous TPDO messages. If it is set,
 * message will not be sent, if curent time is outside synchronous window.
 *
 * @return Pointer to CAN transmit message buffer. 8 bytes data array inside
 * buffer should be written, before CO_CANsend() function is called.
 * Zero is returned in case of wrong arguments.
 */
CO_CANtx_t *CO_CANtxBufferInit(
        CO_CANmodule_t         *CANmodule,
        uint16_t                index,
        uint16_t                ident,
        bool_t                  rtr,
        uint8_t                 noOfBytes,
        bool_t                  syncFlag);

/**
 * Send CAN message.
 * 发送信息函数
 *
 * @param CANmodule This object.
 * @param buffer Pointer to transmit buffer, returned by CO_CANtxBufferInit().
 * Data bytes must be written in buffer before function call.
 *
 * @return #CO_ReturnError_t: CO_ERROR_NO, CO_ERROR_TX_OVERFLOW or
 * CO_ERROR_TX_PDO_WINDOW (Synchronous TPDO is outside window).
 */
CO_ReturnError_t CO_CANsend(CO_CANmodule_t *CANmodule, CO_CANtx_t *buffer);

/**
 * Clear all synchronous TPDOs from CAN module transmit buffers.
 * 在CAN模块中的发送缓冲区清除所有的同步TPDO
 *
 * CANopen allows synchronous PDO communication only inside time between SYNC
 * message and SYNC Window. If time is outside this window, new synchronous PDOs
 * must not be sent and all pending sync TPDOs, which may be on CAN TX buffers,
 * must be cleared.
 *
 * This function checks (and aborts transmission if necessary) CAN TX buffers
 * when it is called. Function should be called by the stack in the moment,
 * when SYNC time was just passed out of synchronous window.
 *
 * @param CANmodule This object.
 */
void CO_CANclearPendingSyncPDOs(CO_CANmodule_t *CANmodule);

/**
 * Verify all errors of CAN module.
 * 校验所有的额错误CAN模块
 *
 * Function is called directly from CO_EM_process() function.
 *
 * @param CANmodule This object.
 */
void CO_CANverifyErrors(CO_CANmodule_t *CANmodule);

/**
 * Receives and transmits CAN messages.
 * 接收、发送CAN信息
 *
 * Function must be called directly from high priority CAN interrupt.
 *
 * @param CANmodule This object.
 */
void CO_CANinterrupt(CO_CANmodule_t *CANmodule);

/** @} */
#endif