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/**
 * CAN communication interface. This is a general, high-level interface for CAN
 * communication. Underlying CAN controllers are abstracted by this interface,
 * so the application needs not work directly with the CAN controllers.
 *
 * The interface is fully queued in both directions. Both queues can configured
 * in terms of size, and can also be disabled completely to save both RAM and
 * FLASH space (the queue routines are removed by preprocessor when queues
 * are disabled). When queues are enabled, the application has to call
 * Can_Service as often as possible, so messages can be moved between the CAN
 * controller and the message queues. This might be handled by interrupts in
 * future. When queues are disabled, on the other hand, the application has
 * to call Can_Receive as often as possible in order not to loose any messages.
 *
 * @date    2006-11-21
 *
 * @author  Jimmy Myhrman
 *  
 */
 
/*-----------------------------------------------------------------------------
 * Includes
 *---------------------------------------------------------------------------*/
//#include <string.h>
#include "can.h"
//#include <mcu.h>
//#include <stdio.h>
//#include <timebase.h>
//#include <assert.h>
#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
    #include "mcp2515/mcp2515.h"
#endif
 
 
/*-----------------------------------------------------------------------------
 * Prerequisites
 *---------------------------------------------------------------------------*/
#ifndef CAN_CONTROLLER
    #error CAN_CONTROLLER not specified! Edit can_cfg.h !
#endif
 
#ifndef CAN_BITRATE
    #error CAN_BITRATE not defined! Edit can_cfg.h !
#endif
 
#ifndef CAN_QUEUE_SIZE_RX
    #error CAN_QUEUE_SIZE_RX not defined! Edit can_cfg.h !
#endif
 
#ifndef CAN_QUEUE_SIZE_TX
    #error CAN_QUEUE_SIZE_TX not defined! Edit can_cfg.h !
#endif
 
#ifndef CAN_CONTROLLER_NR_TX_BUFFERS
    #error CAN_CONTROLLER_NR_TX_BUFFERS not defined! Edit can_cfg.h !
#endif
 
#ifndef CAN_CONTROLLER_NR_RX_BUFFERS
    #error CAN_CONTROLLER_NR_RX_BUFFERS not defined! Edit can_cfg.h !
#endif
 
 
/*-----------------------------------------------------------------------------
 * Type Definitions
 *---------------------------------------------------------------------------*/
 
#if (CAN_QUEUE_SIZE_TX > 0) || (CAN_QUEUE_SIZE_RX > 0)
/**
 * CAN Message Queue Type. Stores and manages several CAN messages
 * in a FIFO structure.
 */
typedef struct {
    Can_Message_t *dataPtr; /* pointer to the data storage */
    uint8_t head;       /* current OUTPUT position */
    uint8_t tail;       /* current INPUT position */
    uint8_t nrElements; /* nr of elements currently queued */
    uint8_t size;       /* total size of the queue */
} Can_MessageQueue_t;
#endif
 
 
/*-----------------------------------------------------------------------------
 * Private (static) variables
 *---------------------------------------------------------------------------*/
 
#if CAN_QUEUE_SIZE_TX > 0
    /* TX queue object and static memory storage buffer for this queue */
    static Can_MessageQueue_t canTxQueue;
    static Can_Message_t canTxQueueDataStorage[CAN_QUEUE_SIZE_TX];
#endif
#if CAN_QUEUE_SIZE_RX > 0
    /* RX queue object and static memory storage buffer for this queue */
    static Can_MessageQueue_t canRxQueue;
    static Can_Message_t canRxQueueDataStorage[CAN_QUEUE_SIZE_RX];
#endif
 
 
/*-----------------------------------------------------------------------------
 * Private Function Prototypes
 *---------------------------------------------------------------------------*/
 
/* functions that deal with the controller hardware */
static Can_Return_t Can_SendImmediately(Can_Message_t *msg);
static Can_Return_t Can_ReceiveFromController(Can_Message_t *msg, uint8_t rxBuffer);
static uint8_t Can_MessagesAvailableInController(void) __attribute__((unused));
static Can_Return_t Can_ControllerCheckError(void) __attribute__((unused));
 
#if (CAN_QUEUE_SIZE_TX > 0) || (CAN_QUEUE_SIZE_RX > 0)
/* functions that deal with the message queues */
static void Can_QueueInit(Can_MessageQueue_t *q, uint8_t size, Can_Message_t *dataPtr);
static Can_Message_t* Can_QueueInsert(Can_MessageQueue_t *q);
static Can_Message_t* Can_QueueReadTailPtr(Can_MessageQueue_t *q);
static void Can_QueueRemoveTail(Can_MessageQueue_t *q);
#endif
 
 
/*-----------------------------------------------------------------------------
 * Public Functions
 *---------------------------------------------------------------------------*/
 
/**
 * Initializes the CAN interface. Edit can_cfg.h to choose bitrate.
 *
 * @return
 *      CAN_OK if initialization was successful.
 *      CAN_INIT_FAIL_SET_BITRATE if bitrate could not be set correctly.
 *      CAN_INIT_FAIL_SET_MODE if the controller could not be set to normal operation mode.
 *      CAN_INIT_FAIL in case of general error.
 */
Can_Return_t Can_Init() {
    #if CAN_QUEUE_SIZE_TX > 0
        /* initialize TX queue */
        Can_QueueInit(&canTxQueue, CAN_QUEUE_SIZE_TX, canTxQueueDataStorage);
    #endif
    #if CAN_QUEUE_SIZE_RX > 0
        /* initialize RX queue */
        Can_QueueInit(&canRxQueue, CAN_QUEUE_SIZE_RX, canRxQueueDataStorage);
    #endif
   
    #if CAN_CONTROLLER == CAN_CONTROLLER_NULL
        /*
         * Initialize null device.
         */
        return CAN_OK;
    #endif
   
    #if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
        /*
         * Initialize MCP2515 device.
         */
        if (MCP2515_Init() != MCP2515_OK) {
            return CAN_FAIL;
        }
        if (MCP2515_SetCanCtrlMode(MODE_NORMAL) != MCP2515_OK) {
            return CAN_FAIL;
        }
        return CAN_OK;
    #endif
   
    return CAN_FAIL;
}
 
 
/**
 * Sends a CAN message. The message will be put into the transmission queue,
 * and hence, it might not be sent immediately. If the queue is full, the
 * message will not be taken care of, and CAN_FAIL is returned.
 *
 * @param msg
 *      Pointer to the CAN message.
 *
 * @return
 *      CAN_OK if the message was successfully enqueued.
 *      CAN_FAIL if the transmission queue is full.
 */
Can_Return_t Can_Send(Can_Message_t *msg) {
    #if CAN_QUEUE_SIZE_TX == 0
        /* TX queue is disabled, so send immediately */
        return Can_SendImmediately(msg);
    #else
        #if 0
        printf("Can_Send()\n\r");
        printf("    queue size before = %u\n\r", canTxQueue.nrElements);
        #endif
        /* check if there is room available in the tx queue */
        if (canTxQueue.nrElements >= canTxQueue.size) {
            #if 0
            printf("    TX queue full!\n\r");
            #endif
            return CAN_FAIL;
        }
        /* put message in queue */
        Can_Message_t *ptr = Can_QueueInsert(&canTxQueue);
        memcpy(ptr, msg, sizeof(Can_Message_t));
        #if 0
        printf("    queue size after = %u\n\r", canTxQueue.nrElements);
        #endif
        return CAN_OK;
    #endif
}
 
 
/**
 * Services the CAN subsystem. Messages waiting in the transmission queue
 * will be transmitted if the controller is not busy, and any messages
 * received by the controller will be moved from the controller buffers
 * into the internal reception queue.
 */
void Can_Service() {
    #if CAN_QUEUE_SIZE_TX > 0
        /* try to transmit messages waiting in the transmission queue */
        for (uint8_t i=0; i<CAN_CONTROLLER_NR_TX_BUFFERS; i++) {
            if (canTxQueue.nrElements > 0) {
                #if 0
                printf("msg in TX queue. trying to send...\n");
                #endif
                /* ensure the queue operations are atomic */
                cli();
                Can_Message_t *txMsg = Can_QueueReadTailPtr(&canTxQueue);
                if (Can_SendImmediately(txMsg) == CAN_OK) {
                    /* transmission OK, remove from queue */
                    Can_QueueRemoveTail(&canTxQueue);
                }
                //TODO: dont enable interrupts, restore previous state
                sei();
            }
            else {
                /* quit the loop if the queue is empty */
                break;
            }
        }
    #endif
   
    #if CAN_QUEUE_SIZE_RX > 0
        /* move all received messages from CAN controller to reception queue */
        Can_Message_t rxMsg;
        /* all RX buffers have to be checked (and in correct order) */
        for (uint8_t buf=0; buf<CAN_CONTROLLER_NR_RX_BUFFERS; buf++) {
            /* if buffer contains a message, handle it */
            if (Can_ReceiveFromController(&rxMsg, buf) == CAN_OK) {
                /* ensure the queue operations are atomic */
                cli();
                /* try to get access to the queue */
                Can_Message_t *destPtr = Can_QueueInsert(&canRxQueue);
                /* if we can insert into queue, copy the message */
                if (destPtr != 0) {
                    memcpy(destPtr, &rxMsg, sizeof(Can_Message_t));
                }
                else {
                    /* otherwise, the received message will be discarded... */
                }
                //TODO: dont enable interrupts, restore previous state
                sei();
            }
        }
    #endif
   
    /* TODO: check error status in controller */
}
 
 
/**
 * Receives a CAN message that is waiting in the reception queue. If no
 * messages have been received, CAN_NO_MSG_AVAILABLE is returned.
 * Otherwise, a CAN message is copied into the specified message buffer
 * and deleted from the internal message reception queue. In this case,
 * CAN_OK is returned.
 *
 * @param msg
 *          Pointer to the message storage buffer into which the message
 *          should be copied.
 *
 * @return
 *          CAN_OK if a received message was successfully copied into the buffer.
 *          CAN_NO_MSG_AVAILABLE if no messages are available.
 */
Can_Return_t Can_Receive(Can_Message_t *msg) {
   
    #if CAN_QUEUE_SIZE_RX > 0
        /*
         * RX queue is enabled, so try to get message from queue.
         */
        Can_Message_t *pSrc;    /* Source pointer */
        /* Check if there is anything available in the RxQueue */
        if (canRxQueue.nrElements == 0) {
            return CAN_NO_MSG_AVAILABLE;
        }
        /* ensure the queue operations are atomic */
        cli();
        pSrc = Can_QueueReadTailPtr(&canRxQueue);
        /* copy frame from queue, and then remove from queue */
        memcpy(msg, pSrc, sizeof(Can_Message_t));
        Can_QueueRemoveTail(&canRxQueue);
        //TODO: dont enable interrupts, restore previous state
        sei();
        /* a message has successfully been copied and removed from queue */
        return CAN_OK;
    #else
        /*
         * RX queue is disabled, so try to get message from controller.
         * We don't know which buffer to get the message from, so best
         * we can do is to get from buf0 first time, and then increase
         * buffer number at each call, finally wrapping around at
         * CAN_CONTROLLER_NR_RX_BUFFERS.
         */
        static uint8_t rxBuffer = 0;
        uint8_t i;
        /* worst case is that we need to check all available rx buffers in order to find a message */
        for (i=0; i<CAN_CONTROLLER_NR_RX_BUFFERS; i++) {
            /* is there a message available in this buffer? */
            if (Can_ReceiveFromController(msg, rxBuffer) == CAN_OK) {
                /* increase buffer number and return the message */
                rxBuffer = (rxBuffer + 1) % CAN_CONTROLLER_NR_RX_BUFFERS;
                return CAN_OK;
            }
            /* increase buffer number so we can check next buffer */
            rxBuffer = (rxBuffer + 1) % CAN_CONTROLLER_NR_RX_BUFFERS;
        }
        /* all buffers were checked, but no message found */
        return CAN_NO_MSG_AVAILABLE;
    #endif
}
 
 
 
/*-----------------------------------------------------------------------------
 * Private Functions
 *---------------------------------------------------------------------------*/  
 
/**
 * Sends a CAN message immediately with the controller hardware. If the CAN
 * controller is busy, the function will return CAN_SEND_FAIL_TX_BUSY.
 *
 * @param msg
 *      Pointer to the CAN message storage buffer.
 *
 * @return
 *      CAN_OK if the message was successfully sent to the controller.
 *      CAN_FAIL if the controller is busy.
 */
static Can_Return_t Can_SendImmediately(Can_Message_t* msg) {
    #if CAN_CONTROLLER == CAN_CONTROLLER_NULL
        /*
         * Send with null device.
         */
        return CAN_OK;
    #endif
 
    #if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
        /*
         * Send with MCP2515 device.
         */
        uint8_t res, txbuf_n;
        res = MCP2515_GetNextFreeTXBuf(&txbuf_n); // info = addr.
        if (res == MCP_ALLTXBUSY) {
            return CAN_FAIL;
        }
        MCP2515_WriteCanMsg(txbuf_n, msg);
        MCP2515_StartTransmit(txbuf_n);
        return CAN_OK;
    #endif
}
 
 
/**
 * Receives a CAN message from the CAN controller hardware.
 *
 * @param msg
 *      Pointer to the message storage buffer into which the message should be copied.
 *
 * @param rxBuffer
 *      Identifies the RX buffer in the controller. Range is [0,CAN_CONTROLLER_NR_RX_BUFFERS-1].
 *
 * @return
 *      CAN_OK if a received message was successfully copied into the buffer.
 *      CAN_NO_MSG_AVAILABLE if there are is no message available in the specified buffer.
 *      CAN_FAIL if the rxBuffer parameter i out of range for the specified controller.
 */
static Can_Return_t Can_ReceiveFromController(Can_Message_t *msg, uint8_t rxBuffer) {
    #if CAN_CONTROLLER == CAN_CONTROLLER_NULL
        /*
         * Receive from null device.
         */
        return CAN_NO_MSG_AVAILABLE;
    #endif
   
    #if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
        /*
         * Receive from MCP2515 device.
         */
        uint8_t stat;
        stat = MCP2515_ReadStatus();
        if (rxBuffer == 0) {
            /* check BUF0 */
            if (stat & MCP_STAT_RX0IF) {
                /* Msg in Buffer 0 */
                MCP2515_ReadCanMsg(MCP_RXBUF_0, msg);
                MCP2515_ModifyRegister(MCP_CANINTF, MCP_RX0IF, 0);
                return CAN_OK;
            }
        }
        else if (rxBuffer == 1) {
            /* check BUF1 */
            if (stat & MCP_STAT_RX1IF) {
                /* Msg in Buffer 1 */
                MCP2515_ReadCanMsg(MCP_RXBUF_1, msg);
                MCP2515_ModifyRegister(MCP_CANINTF, MCP_RX1IF, 0);
                return CAN_OK;
            }
        }
        else {
            /* invalid parameters */
            return CAN_FAIL;
        }
        return CAN_NO_MSG_AVAILABLE;
    #endif
}
 
 
/**
 * Checks how many messages are available in the CAN controller hardware.
 *
 * @return
 *      The number of messages available (0 if none).
 */
static uint8_t Can_MessagesAvailableInController() {
    #if CAN_CONTROLLER == CAN_CONTROLLER_NULL
        /*
         * Check for messages in null device.
         */
        return 0;
    #endif
   
    #if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
        /*
         * Check for message in MCP2515 device.
         */
        uint8_t res;
        res = MCP2515_ReadStatus(); /* RXnIF in Bit 1 and 0 */
        if (res & MCP_STAT_RXIF_MASK) {
            //TODO: check how many messages are available
            return 1;   /* at least one message available */
        }
        else {
            return 0;   /* no messages available */
        }
    #endif
   
    return 0;
}
 
 
/*
 * Checks Controller-Error-State.
 *
 * @return
 *      CAN_OK if the controller is OK.
 *      CAN_FAIL if errors have occured.
 *
 * @todo
 *      Styr upp denna funktion lite b�ttre.
 */
static Can_Return_t Can_ControllerCheckError() {
    #if CAN_CONTROLLER == CAN_CONTROLLER_NULL
        /*
         * Check for errors in null device.
         */
        return CAN_OK;
    #endif
   
    #if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
        /*
         * Check for errors in MCP2515 device.
         */
        uint8_t eflg = MCP2515_ReadRegister(MCP_EFLG);
        if (eflg & MCP_EFLG_ERRORMASK) {
            return CAN_FAIL;    /* errors found */
        }
        else {
            return CAN_OK;      /* no errors found */
        }
    #endif
}
 
 
#if (CAN_QUEUE_SIZE_TX > 0) || (CAN_QUEUE_SIZE_RX > 0)
/**
 * Initializes a CAN queue.
 *
 * @param q
 *      Pointer to the queue object.
 *
 * @param size
 *      Size of the queue (number of messages that can be queued).
 *
 * @param dataPtr
 *      Pointer to the message storage buffer that should be used by the queue.
 */
static void Can_QueueInit(Can_MessageQueue_t *q, uint8_t size, Can_Message_t *dataPtr) {
    q->dataPtr = dataPtr;
    q->head = 0;
    q->tail = 0;
    q->nrElements = 0;
    q->size = size;
}
 
 
/**
 * Inserts a new element in a queue and returns a pointer to the new element.
 * If the queue is full, the last element (the tail) will be overwritten by
 * the new element.
 *
 * @param q
 *      Pointer to the queue object.
 *
 * @return
 *      Pointer to the new message element. Use this pointer to copy data into the queue.
 */
static Can_Message_t* Can_QueueInsert(Can_MessageQueue_t *q) {
    Can_Message_t *ptr;
    #if 0
    printf("INSERT: bef=%u, ", q->nrElements);
    #endif
    if ((q->nrElements+1) > q->size) {
        q->tail = (q->tail + 1) % q->size;
        q->nrElements--;
    #if 0
        printf("Can_QueueInsertViaPtr: QUEUE OVERRUN!\n\r");
    #endif
    }
    ptr = &(q->dataPtr[q->head]);
    #if 0
    if (q->handled[q->head] == 0) {
        printf("Can_QueueInsertViaPtr: discarding non-handled msg!\n\r");
    }
    #endif
    q->head = (q->head + 1) % q->size;
    q->nrElements++;
    #if 0
    printf("aft=%u\n\n", q->nrElements);
    #endif
    return ptr;
}
 
 
/**
 * Returns a pointer to the last element in the queue (the tail). Use this pointer
 * to extract the message, and then call Can_QueueRemoveTail to actually remove
 * the element.
 *
 * @param q
 *      Pointer to the queue object.
 *
 * @return
 *      Pointer to the tail message element.
 */
static Can_Message_t* Can_QueueReadTailPtr(Can_MessageQueue_t *q) {
    if (q->nrElements > 0) {
        return &(q->dataPtr[q->tail]);
    }
    else {
        return 0;
    }
}
 
 
/**
 * Removes the last element in the queue (the tail). You should have extracted
 * the data using Can_QueueReadTailPtr before using this function.
 *
 * @param q
 *      Pointer to the queue object.
 */
static void Can_QueueRemoveTail(Can_MessageQueue_t *q) {
    if (q->nrElements > 0) {
        q->tail = (q->tail + 1) % q->size;
        q->nrElements--;
        #if 0
        printf("queue size = %u\n", q->nrElements);
        #endif
    }
}
 
#endif
 

Rev 240	Rev 244
1	/**	1	/**
2	* CAN communication interface. This is a general, high-level interface for CAN	2	* CAN communication interface. This is a general, high-level interface for CAN
3	* communication. Underlying CAN controllers are abstracted by this interface,	3	* communication. Underlying CAN controllers are abstracted by this interface,
4	* so the application needs not work directly with the CAN controllers.	4	* so the application needs not work directly with the CAN controllers.
5	*	5	*
6	* The interface is fully queued in both directions. Both queues can configured	6	* The interface is fully queued in both directions. Both queues can configured
7	* in terms of size, and can also be disabled completely to save both RAM and	7	* in terms of size, and can also be disabled completely to save both RAM and
8	* FLASH space (the queue routines are removed by preprocessor when queues	8	* FLASH space (the queue routines are removed by preprocessor when queues
9	* are disabled). When queues are enabled, the application has to call	9	* are disabled). When queues are enabled, the application has to call
10	* Can_Service as often as possible, so messages can be moved between the CAN	10	* Can_Service as often as possible, so messages can be moved between the CAN
11	* controller and the message queues. This might be handled by interrupts in	11	* controller and the message queues. This might be handled by interrupts in
12	* future. When queues are disabled, on the other hand, the application has	12	* future. When queues are disabled, on the other hand, the application has
13	* to call Can_Receive as often as possible in order not to loose any messages.	13	* to call Can_Receive as often as possible in order not to loose any messages.
14	*	14	*
15	* @date 2006-11-21	15	* @date 2006-11-21
16	*	16	*
17	* @author Jimmy Myhrman	17	* @author Jimmy Myhrman
18	*	18	*
19	*/	19	*/
20		20
21	/*-----------------------------------------------------------------------------	21	/*-----------------------------------------------------------------------------
22	* Includes	22	* Includes
23	---------------------------------------------------------------------------/	23	---------------------------------------------------------------------------/
24	//#include <string.h>	24	//#include <string.h>
25	#include "can.h"	25	#include "can.h"
26	//#include <mcu.h>	26	//#include <mcu.h>
27	//#include <stdio.h>	27	//#include <stdio.h>
28	//#include <timebase.h>	28	//#include <timebase.h>
29	//#include <assert.h>	29	//#include <assert.h>
30	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515	30	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
31	#include "mcp2515/mcp2515.h"	31	#include "mcp2515/mcp2515.h"
32	#endif	32	#endif
33		33
34		34
35	/*-----------------------------------------------------------------------------	35	/*-----------------------------------------------------------------------------
36	* Prerequisites	36	* Prerequisites
37	---------------------------------------------------------------------------/	37	---------------------------------------------------------------------------/
38	#ifndef CAN_CONTROLLER	38	#ifndef CAN_CONTROLLER
39	#error CAN_CONTROLLER not specified! Edit can_cfg.h !	39	#error CAN_CONTROLLER not specified! Edit can_cfg.h !
40	#endif	40	#endif
41		41
42	#ifndef CAN_BITRATE	42	#ifndef CAN_BITRATE
43	#error CAN_BITRATE not defined! Edit can_cfg.h !	43	#error CAN_BITRATE not defined! Edit can_cfg.h !
44	#endif	44	#endif
45		45
46	#ifndef CAN_QUEUE_SIZE_RX	46	#ifndef CAN_QUEUE_SIZE_RX
47	#error CAN_QUEUE_SIZE_RX not defined! Edit can_cfg.h !	47	#error CAN_QUEUE_SIZE_RX not defined! Edit can_cfg.h !
48	#endif	48	#endif
49		49
50	#ifndef CAN_QUEUE_SIZE_TX	50	#ifndef CAN_QUEUE_SIZE_TX
51	#error CAN_QUEUE_SIZE_TX not defined! Edit can_cfg.h !	51	#error CAN_QUEUE_SIZE_TX not defined! Edit can_cfg.h !
52	#endif	52	#endif
53		53
54	#ifndef CAN_CONTROLLER_NR_TX_BUFFERS	54	#ifndef CAN_CONTROLLER_NR_TX_BUFFERS
55	#error CAN_CONTROLLER_NR_TX_BUFFERS not defined! Edit can_cfg.h !	55	#error CAN_CONTROLLER_NR_TX_BUFFERS not defined! Edit can_cfg.h !
56	#endif	56	#endif
57		57
58	#ifndef CAN_CONTROLLER_NR_RX_BUFFERS	58	#ifndef CAN_CONTROLLER_NR_RX_BUFFERS
59	#error CAN_CONTROLLER_NR_RX_BUFFERS not defined! Edit can_cfg.h !	59	#error CAN_CONTROLLER_NR_RX_BUFFERS not defined! Edit can_cfg.h !
60	#endif	60	#endif
61		61
62		62
63	/*-----------------------------------------------------------------------------	63	/*-----------------------------------------------------------------------------
64	* Type Definitions	64	* Type Definitions
65	---------------------------------------------------------------------------/	65	---------------------------------------------------------------------------/
66		66
67	#if (CAN_QUEUE_SIZE_TX > 0) \|\| (CAN_QUEUE_SIZE_RX > 0)	67	#if (CAN_QUEUE_SIZE_TX > 0) \|\| (CAN_QUEUE_SIZE_RX > 0)
68	/**	68	/**
69	* CAN Message Queue Type. Stores and manages several CAN messages	69	* CAN Message Queue Type. Stores and manages several CAN messages
70	* in a FIFO structure.	70	* in a FIFO structure.
71	*/	71	*/
72	typedef struct {	72	typedef struct {
73	Can_Message_t dataPtr; / pointer to the data storage */	73	Can_Message_t dataPtr; / pointer to the data storage */
74	uint8_t head; /* current OUTPUT position */	74	uint8_t head; /* current OUTPUT position */
75	uint8_t tail; /* current INPUT position */	75	uint8_t tail; /* current INPUT position */
76	uint8_t nrElements; /* nr of elements currently queued */	76	uint8_t nrElements; /* nr of elements currently queued */
77	uint8_t size; /* total size of the queue */	77	uint8_t size; /* total size of the queue */
78	} Can_MessageQueue_t;	78	} Can_MessageQueue_t;
79	#endif	79	#endif
80		80
81		81
82	/*-----------------------------------------------------------------------------	82	/*-----------------------------------------------------------------------------
83	* Private (static) variables	83	* Private (static) variables
84	---------------------------------------------------------------------------/	84	---------------------------------------------------------------------------/
85		85
86	#if CAN_QUEUE_SIZE_TX > 0	86	#if CAN_QUEUE_SIZE_TX > 0
87	/* TX queue object and static memory storage buffer for this queue */	87	/* TX queue object and static memory storage buffer for this queue */
88	static Can_MessageQueue_t canTxQueue;	88	static Can_MessageQueue_t canTxQueue;
89	static Can_Message_t canTxQueueDataStorage[CAN_QUEUE_SIZE_TX];	89	static Can_Message_t canTxQueueDataStorage[CAN_QUEUE_SIZE_TX];
90	#endif	90	#endif
91	#if CAN_QUEUE_SIZE_RX > 0	91	#if CAN_QUEUE_SIZE_RX > 0
92	/* RX queue object and static memory storage buffer for this queue */	92	/* RX queue object and static memory storage buffer for this queue */
93	static Can_MessageQueue_t canRxQueue;	93	static Can_MessageQueue_t canRxQueue;
94	static Can_Message_t canRxQueueDataStorage[CAN_QUEUE_SIZE_RX];	94	static Can_Message_t canRxQueueDataStorage[CAN_QUEUE_SIZE_RX];
95	#endif	95	#endif
96		96
97		97
98	/*-----------------------------------------------------------------------------	98	/*-----------------------------------------------------------------------------
99	* Private Function Prototypes	99	* Private Function Prototypes
100	---------------------------------------------------------------------------/	100	---------------------------------------------------------------------------/
101		101
102	/* functions that deal with the controller hardware */	102	/* functions that deal with the controller hardware */
103	static Can_Return_t Can_SendImmediately(Can_Message_t *msg);	103	static Can_Return_t Can_SendImmediately(Can_Message_t *msg);
104	static Can_Return_t Can_ReceiveFromController(Can_Message_t *msg, uint8_t rxBuffer);	104	static Can_Return_t Can_ReceiveFromController(Can_Message_t *msg, uint8_t rxBuffer);
105	static uint8_t Can_MessagesAvailableInController(void) __attribute__((unused));	105	static uint8_t Can_MessagesAvailableInController(void) __attribute__((unused));
106	static Can_Return_t Can_ControllerCheckError(void) __attribute__((unused));	106	static Can_Return_t Can_ControllerCheckError(void) __attribute__((unused));
107		107
108	#if (CAN_QUEUE_SIZE_TX > 0) \|\| (CAN_QUEUE_SIZE_RX > 0)	108	#if (CAN_QUEUE_SIZE_TX > 0) \|\| (CAN_QUEUE_SIZE_RX > 0)
109	/* functions that deal with the message queues */	109	/* functions that deal with the message queues */
110	static void Can_QueueInit(Can_MessageQueue_t q, uint8_t size, Can_Message_t dataPtr);	110	static void Can_QueueInit(Can_MessageQueue_t q, uint8_t size, Can_Message_t dataPtr);
111	static Can_Message_t* Can_QueueInsert(Can_MessageQueue_t *q);	111	static Can_Message_t* Can_QueueInsert(Can_MessageQueue_t *q);
112	static Can_Message_t* Can_QueueReadTailPtr(Can_MessageQueue_t *q);	112	static Can_Message_t* Can_QueueReadTailPtr(Can_MessageQueue_t *q);
113	static void Can_QueueRemoveTail(Can_MessageQueue_t *q);	113	static void Can_QueueRemoveTail(Can_MessageQueue_t *q);
114	#endif	114	#endif
115		115
116		116
117	/*-----------------------------------------------------------------------------	117	/*-----------------------------------------------------------------------------
118	* Public Functions	118	* Public Functions
119	---------------------------------------------------------------------------/	119	---------------------------------------------------------------------------/
120		120
121	/**	121	/**
122	* Initializes the CAN interface. Edit can_cfg.h to choose bitrate.	122	* Initializes the CAN interface. Edit can_cfg.h to choose bitrate.
123	*	123	*
124	* @return	124	* @return
125	* CAN_OK if initialization was successful.	125	* CAN_OK if initialization was successful.
126	* CAN_INIT_FAIL_SET_BITRATE if bitrate could not be set correctly.	126	* CAN_INIT_FAIL_SET_BITRATE if bitrate could not be set correctly.
127	* CAN_INIT_FAIL_SET_MODE if the controller could not be set to normal operation mode.	127	* CAN_INIT_FAIL_SET_MODE if the controller could not be set to normal operation mode.
128	* CAN_INIT_FAIL in case of general error.	128	* CAN_INIT_FAIL in case of general error.
129	*/	129	*/
130	Can_Return_t Can_Init() {	130	Can_Return_t Can_Init() {
131	#if CAN_QUEUE_SIZE_TX > 0	131	#if CAN_QUEUE_SIZE_TX > 0
132	/* initialize TX queue */	132	/* initialize TX queue */
133	Can_QueueInit(&canTxQueue, CAN_QUEUE_SIZE_TX, canTxQueueDataStorage);	133	Can_QueueInit(&canTxQueue, CAN_QUEUE_SIZE_TX, canTxQueueDataStorage);
134	#endif	134	#endif
135	#if CAN_QUEUE_SIZE_RX > 0	135	#if CAN_QUEUE_SIZE_RX > 0
136	/* initialize RX queue */	136	/* initialize RX queue */
137	Can_QueueInit(&canRxQueue, CAN_QUEUE_SIZE_RX, canRxQueueDataStorage);	137	Can_QueueInit(&canRxQueue, CAN_QUEUE_SIZE_RX, canRxQueueDataStorage);
138	#endif	138	#endif
139		139
140	#if CAN_CONTROLLER == CAN_CONTROLLER_NULL	140	#if CAN_CONTROLLER == CAN_CONTROLLER_NULL
141	/*	141	/*
142	* Initialize null device.	142	* Initialize null device.
143	*/	143	*/
144	return CAN_OK;	144	return CAN_OK;
145	#endif	145	#endif
146		146
147	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515	147	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
148	/*	148	/*
149	* Initialize MCP2515 device.	149	* Initialize MCP2515 device.
150	*/	150	*/
151	if (MCP2515_Init(~~CAN_BITRATE~~) != MCP2515_OK) {	151	if (MCP2515_Init() != MCP2515_OK) {
152	return CAN_FAIL;	152	return CAN_FAIL;
153	}	153	}
154	if (MCP2515_SetCanCtrlMode(MODE_NORMAL) != MCP2515_OK) {	154	if (MCP2515_SetCanCtrlMode(MODE_NORMAL) != MCP2515_OK) {
155	return CAN_FAIL;	155	return CAN_FAIL;
156	}	156	}
157	return CAN_OK;	157	return CAN_OK;
158	#endif	158	#endif
159		159
160	return CAN_FAIL;	160	return CAN_FAIL;
161	}	161	}
162		162
163		163
164	/**	164	/**
165	* Sends a CAN message. The message will be put into the transmission queue,	165	* Sends a CAN message. The message will be put into the transmission queue,
166	* and hence, it might not be sent immediately. If the queue is full, the	166	* and hence, it might not be sent immediately. If the queue is full, the
167	* message will not be taken care of, and CAN_FAIL is returned.	167	* message will not be taken care of, and CAN_FAIL is returned.
168	*	168	*
169	* @param msg	169	* @param msg
170	* Pointer to the CAN message.	170	* Pointer to the CAN message.
171	*	171	*
172	* @return	172	* @return
173	* CAN_OK if the message was successfully enqueued.	173	* CAN_OK if the message was successfully enqueued.
174	* CAN_FAIL if the transmission queue is full.	174	* CAN_FAIL if the transmission queue is full.
175	*/	175	*/
176	Can_Return_t Can_Send(Can_Message_t *msg) {	176	Can_Return_t Can_Send(Can_Message_t *msg) {
177	#if CAN_QUEUE_SIZE_TX == 0	177	#if CAN_QUEUE_SIZE_TX == 0
178	/* TX queue is disabled, so send immediately */	178	/* TX queue is disabled, so send immediately */
179	return Can_SendImmediately(msg);	179	return Can_SendImmediately(msg);
180	#else	180	#else
181	#if 0	181	#if 0
182	printf("Can_Send()\n\r");	182	printf("Can_Send()\n\r");
183	printf(" queue size before = %u\n\r", canTxQueue.nrElements);	183	printf(" queue size before = %u\n\r", canTxQueue.nrElements);
184	#endif	184	#endif
185	/* check if there is room available in the tx queue */	185	/* check if there is room available in the tx queue */
186	if (canTxQueue.nrElements >= canTxQueue.size) {	186	if (canTxQueue.nrElements >= canTxQueue.size) {
187	#if 0	187	#if 0
188	printf(" TX queue full!\n\r");	188	printf(" TX queue full!\n\r");
189	#endif	189	#endif
190	return CAN_FAIL;	190	return CAN_FAIL;
191	}	191	}
192	/* put message in queue */	192	/* put message in queue */
193	Can_Message_t *ptr = Can_QueueInsert(&canTxQueue);	193	Can_Message_t *ptr = Can_QueueInsert(&canTxQueue);
194	memcpy(ptr, msg, sizeof(Can_Message_t));	194	memcpy(ptr, msg, sizeof(Can_Message_t));
195	#if 0	195	#if 0
196	printf(" queue size after = %u\n\r", canTxQueue.nrElements);	196	printf(" queue size after = %u\n\r", canTxQueue.nrElements);
197	#endif	197	#endif
198	return CAN_OK;	198	return CAN_OK;
199	#endif	199	#endif
200	}	200	}
201		201
202		202
203	/**	203	/**
204	* Services the CAN subsystem. Messages waiting in the transmission queue	204	* Services the CAN subsystem. Messages waiting in the transmission queue
205	* will be transmitted if the controller is not busy, and any messages	205	* will be transmitted if the controller is not busy, and any messages
206	* received by the controller will be moved from the controller buffers	206	* received by the controller will be moved from the controller buffers
207	* into the internal reception queue.	207	* into the internal reception queue.
208	*/	208	*/
209	void Can_Service() {	209	void Can_Service() {
210	#if CAN_QUEUE_SIZE_TX > 0	210	#if CAN_QUEUE_SIZE_TX > 0
211	/* try to transmit messages waiting in the transmission queue */	211	/* try to transmit messages waiting in the transmission queue */
212	for (uint8_t i=0; i<CAN_CONTROLLER_NR_TX_BUFFERS; i++) {	212	for (uint8_t i=0; i<CAN_CONTROLLER_NR_TX_BUFFERS; i++) {
213	if (canTxQueue.nrElements > 0) {	213	if (canTxQueue.nrElements > 0) {
214	#if 0	214	#if 0
215	printf("msg in TX queue. trying to send...\n");	215	printf("msg in TX queue. trying to send...\n");
216	#endif	216	#endif
217	/* ensure the queue operations are atomic */	217	/* ensure the queue operations are atomic */
218	cli();	218	cli();
219	Can_Message_t *txMsg = Can_QueueReadTailPtr(&canTxQueue);	219	Can_Message_t *txMsg = Can_QueueReadTailPtr(&canTxQueue);
220	if (Can_SendImmediately(txMsg) == CAN_OK) {	220	if (Can_SendImmediately(txMsg) == CAN_OK) {
221	/* transmission OK, remove from queue */	221	/* transmission OK, remove from queue */
222	Can_QueueRemoveTail(&canTxQueue);	222	Can_QueueRemoveTail(&canTxQueue);
223	}	223	}
224	//TODO: dont enable interrupts, restore previous state	224	//TODO: dont enable interrupts, restore previous state
225	sei();	225	sei();
226	}	226	}
227	else {	227	else {
228	/* quit the loop if the queue is empty */	228	/* quit the loop if the queue is empty */
229	break;	229	break;
230	}	230	}
231	}	231	}
232	#endif	232	#endif
233		233
234	#if CAN_QUEUE_SIZE_RX > 0	234	#if CAN_QUEUE_SIZE_RX > 0
235	/* move all received messages from CAN controller to reception queue */	235	/* move all received messages from CAN controller to reception queue */
236	Can_Message_t rxMsg;	236	Can_Message_t rxMsg;
237	/* all RX buffers have to be checked (and in correct order) */	237	/* all RX buffers have to be checked (and in correct order) */
238	for (uint8_t buf=0; buf<CAN_CONTROLLER_NR_RX_BUFFERS; buf++) {	238	for (uint8_t buf=0; buf<CAN_CONTROLLER_NR_RX_BUFFERS; buf++) {
239	/* if buffer contains a message, handle it */	239	/* if buffer contains a message, handle it */
240	if (Can_ReceiveFromController(&rxMsg, buf) == CAN_OK) {	240	if (Can_ReceiveFromController(&rxMsg, buf) == CAN_OK) {
241	/* ensure the queue operations are atomic */	241	/* ensure the queue operations are atomic */
242	cli();	242	cli();
243	/* try to get access to the queue */	243	/* try to get access to the queue */
244	Can_Message_t *destPtr = Can_QueueInsert(&canRxQueue);	244	Can_Message_t *destPtr = Can_QueueInsert(&canRxQueue);
245	/* if we can insert into queue, copy the message */	245	/* if we can insert into queue, copy the message */
246	if (destPtr != 0) {	246	if (destPtr != 0) {
247	memcpy(destPtr, &rxMsg, sizeof(Can_Message_t));	247	memcpy(destPtr, &rxMsg, sizeof(Can_Message_t));
248	}	248	}
249	else {	249	else {
250	/* otherwise, the received message will be discarded... */	250	/* otherwise, the received message will be discarded... */
251	}	251	}
252	//TODO: dont enable interrupts, restore previous state	252	//TODO: dont enable interrupts, restore previous state
253	sei();	253	sei();
254	}	254	}
255	}	255	}
256	#endif	256	#endif
257		257
258	/* TODO: check error status in controller */	258	/* TODO: check error status in controller */
259	}	259	}
260		260
261		261
262	/**	262	/**
263	* Receives a CAN message that is waiting in the reception queue. If no	263	* Receives a CAN message that is waiting in the reception queue. If no
264	* messages have been received, CAN_NO_MSG_AVAILABLE is returned.	264	* messages have been received, CAN_NO_MSG_AVAILABLE is returned.
265	* Otherwise, a CAN message is copied into the specified message buffer	265	* Otherwise, a CAN message is copied into the specified message buffer
266	* and deleted from the internal message reception queue. In this case,	266	* and deleted from the internal message reception queue. In this case,
267	* CAN_OK is returned.	267	* CAN_OK is returned.
268	*	268	*
269	* @param msg	269	* @param msg
270	* Pointer to the message storage buffer into which the message	270	* Pointer to the message storage buffer into which the message
271	* should be copied.	271	* should be copied.
272	*	272	*
273	* @return	273	* @return
274	* CAN_OK if a received message was successfully copied into the buffer.	274	* CAN_OK if a received message was successfully copied into the buffer.
275	* CAN_NO_MSG_AVAILABLE if no messages are available.	275	* CAN_NO_MSG_AVAILABLE if no messages are available.
276	*/	276	*/
277	Can_Return_t Can_Receive(Can_Message_t *msg) {	277	Can_Return_t Can_Receive(Can_Message_t *msg) {
278		278
279	#if CAN_QUEUE_SIZE_RX > 0	279	#if CAN_QUEUE_SIZE_RX > 0
280	/*	280	/*
281	* RX queue is enabled, so try to get message from queue.	281	* RX queue is enabled, so try to get message from queue.
282	*/	282	*/
283	Can_Message_t pSrc; / Source pointer */	283	Can_Message_t pSrc; / Source pointer */
284	/* Check if there is anything available in the RxQueue */	284	/* Check if there is anything available in the RxQueue */
285	if (canRxQueue.nrElements == 0) {	285	if (canRxQueue.nrElements == 0) {
286	return CAN_NO_MSG_AVAILABLE;	286	return CAN_NO_MSG_AVAILABLE;
287	}	287	}
288	/* ensure the queue operations are atomic */	288	/* ensure the queue operations are atomic */
289	cli();	289	cli();
290	pSrc = Can_QueueReadTailPtr(&canRxQueue);	290	pSrc = Can_QueueReadTailPtr(&canRxQueue);
291	/* copy frame from queue, and then remove from queue */	291	/* copy frame from queue, and then remove from queue */
292	memcpy(msg, pSrc, sizeof(Can_Message_t));	292	memcpy(msg, pSrc, sizeof(Can_Message_t));
293	Can_QueueRemoveTail(&canRxQueue);	293	Can_QueueRemoveTail(&canRxQueue);
294	//TODO: dont enable interrupts, restore previous state	294	//TODO: dont enable interrupts, restore previous state
295	sei();	295	sei();
296	/* a message has successfully been copied and removed from queue */	296	/* a message has successfully been copied and removed from queue */
297	return CAN_OK;	297	return CAN_OK;
298	#else	298	#else
299	/*	299	/*
300	* RX queue is disabled, so try to get message from controller.	300	* RX queue is disabled, so try to get message from controller.
301	* We don't know which buffer to get the message from, so best	301	* We don't know which buffer to get the message from, so best
302	* we can do is to get from buf0 first time, and then increase	302	* we can do is to get from buf0 first time, and then increase
303	* buffer number at each call, finally wrapping around at	303	* buffer number at each call, finally wrapping around at
304	* CAN_CONTROLLER_NR_RX_BUFFERS.	304	* CAN_CONTROLLER_NR_RX_BUFFERS.
305	*/	305	*/
306	static uint8_t rxBuffer = 0;	306	static uint8_t rxBuffer = 0;
307	uint8_t i;	307	uint8_t i;
308	/* worst case is that we need to check all available rx buffers in order to find a message */	308	/* worst case is that we need to check all available rx buffers in order to find a message */
309	for (i=0; i<CAN_CONTROLLER_NR_RX_BUFFERS; i++) {	309	for (i=0; i<CAN_CONTROLLER_NR_RX_BUFFERS; i++) {
310	/* is there a message available in this buffer? */	310	/* is there a message available in this buffer? */
311	if (Can_ReceiveFromController(msg, rxBuffer) == CAN_OK) {	311	if (Can_ReceiveFromController(msg, rxBuffer) == CAN_OK) {
312	/* increase buffer number and return the message */	312	/* increase buffer number and return the message */
313	rxBuffer = (rxBuffer + 1) % CAN_CONTROLLER_NR_RX_BUFFERS;	313	rxBuffer = (rxBuffer + 1) % CAN_CONTROLLER_NR_RX_BUFFERS;
314	return CAN_OK;	314	return CAN_OK;
315	}	315	}
316	/* increase buffer number so we can check next buffer */	316	/* increase buffer number so we can check next buffer */
317	rxBuffer = (rxBuffer + 1) % CAN_CONTROLLER_NR_RX_BUFFERS;	317	rxBuffer = (rxBuffer + 1) % CAN_CONTROLLER_NR_RX_BUFFERS;
318	}	318	}
319	/* all buffers were checked, but no message found */	319	/* all buffers were checked, but no message found */
320	return CAN_NO_MSG_AVAILABLE;	320	return CAN_NO_MSG_AVAILABLE;
321	#endif	321	#endif
322	}	322	}
323		323
324		324
325		325
326	/*-----------------------------------------------------------------------------	326	/*-----------------------------------------------------------------------------
327	* Private Functions	327	* Private Functions
328	---------------------------------------------------------------------------/	328	---------------------------------------------------------------------------/
329		329
330	/**	330	/**
331	* Sends a CAN message immediately with the controller hardware. If the CAN	331	* Sends a CAN message immediately with the controller hardware. If the CAN
332	* controller is busy, the function will return CAN_SEND_FAIL_TX_BUSY.	332	* controller is busy, the function will return CAN_SEND_FAIL_TX_BUSY.
333	*	333	*
334	* @param msg	334	* @param msg
335	* Pointer to the CAN message storage buffer.	335	* Pointer to the CAN message storage buffer.
336	*	336	*
337	* @return	337	* @return
338	* CAN_OK if the message was successfully sent to the controller.	338	* CAN_OK if the message was successfully sent to the controller.
339	* CAN_FAIL if the controller is busy.	339	* CAN_FAIL if the controller is busy.
340	*/	340	*/
341	static Can_Return_t Can_SendImmediately(Can_Message_t* msg) {	341	static Can_Return_t Can_SendImmediately(Can_Message_t* msg) {
342	#if CAN_CONTROLLER == CAN_CONTROLLER_NULL	342	#if CAN_CONTROLLER == CAN_CONTROLLER_NULL
343	/*	343	/*
344	* Send with null device.	344	* Send with null device.
345	*/	345	*/
346	return CAN_OK;	346	return CAN_OK;
347	#endif	347	#endif
348		348
349	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515	349	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
350	/*	350	/*
351	* Send with MCP2515 device.	351	* Send with MCP2515 device.
352	*/	352	*/
353	uint8_t res, txbuf_n;	353	uint8_t res, txbuf_n;
354	res = MCP2515_GetNextFreeTXBuf(&txbuf_n); // info = addr.	354	res = MCP2515_GetNextFreeTXBuf(&txbuf_n); // info = addr.
355	if (res == MCP_ALLTXBUSY) {	355	if (res == MCP_ALLTXBUSY) {
356	return CAN_FAIL;	356	return CAN_FAIL;
357	}	357	}
358	MCP2515_WriteCanMsg(txbuf_n, msg);	358	MCP2515_WriteCanMsg(txbuf_n, msg);
359	MCP2515_StartTransmit(txbuf_n);	359	MCP2515_StartTransmit(txbuf_n);
360	return CAN_OK;	360	return CAN_OK;
361	#endif	361	#endif
362	}	362	}
363		363
364		364
365	/**	365	/**
366	* Receives a CAN message from the CAN controller hardware.	366	* Receives a CAN message from the CAN controller hardware.
367	*	367	*
368	* @param msg	368	* @param msg
369	* Pointer to the message storage buffer into which the message should be copied.	369	* Pointer to the message storage buffer into which the message should be copied.
370	*	370	*
371	* @param rxBuffer	371	* @param rxBuffer
372	* Identifies the RX buffer in the controller. Range is [0,CAN_CONTROLLER_NR_RX_BUFFERS-1].	372	* Identifies the RX buffer in the controller. Range is [0,CAN_CONTROLLER_NR_RX_BUFFERS-1].
373	*	373	*
374	* @return	374	* @return
375	* CAN_OK if a received message was successfully copied into the buffer.	375	* CAN_OK if a received message was successfully copied into the buffer.
376	* CAN_NO_MSG_AVAILABLE if there are is no message available in the specified buffer.	376	* CAN_NO_MSG_AVAILABLE if there are is no message available in the specified buffer.
377	* CAN_FAIL if the rxBuffer parameter i out of range for the specified controller.	377	* CAN_FAIL if the rxBuffer parameter i out of range for the specified controller.
378	*/	378	*/
379	static Can_Return_t Can_ReceiveFromController(Can_Message_t *msg, uint8_t rxBuffer) {	379	static Can_Return_t Can_ReceiveFromController(Can_Message_t *msg, uint8_t rxBuffer) {
380	#if CAN_CONTROLLER == CAN_CONTROLLER_NULL	380	#if CAN_CONTROLLER == CAN_CONTROLLER_NULL
381	/*	381	/*
382	* Receive from null device.	382	* Receive from null device.
383	*/	383	*/
384	return CAN_NO_MSG_AVAILABLE;	384	return CAN_NO_MSG_AVAILABLE;
385	#endif	385	#endif
386		386
387	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515	387	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
388	/*	388	/*
389	* Receive from MCP2515 device.	389	* Receive from MCP2515 device.
390	*/	390	*/
391	uint8_t stat;	391	uint8_t stat;
392	stat = MCP2515_ReadStatus();	392	stat = MCP2515_ReadStatus();
393	if (rxBuffer == 0) {	393	if (rxBuffer == 0) {
394	/* check BUF0 */	394	/* check BUF0 */
395	if (stat & MCP_STAT_RX0IF) {	395	if (stat & MCP_STAT_RX0IF) {
396	/* Msg in Buffer 0 */	396	/* Msg in Buffer 0 */
397	MCP2515_ReadCanMsg(MCP_RXBUF_0, msg);	397	MCP2515_ReadCanMsg(MCP_RXBUF_0, msg);
398	MCP2515_ModifyRegister(MCP_CANINTF, MCP_RX0IF, 0);	398	MCP2515_ModifyRegister(MCP_CANINTF, MCP_RX0IF, 0);
399	return CAN_OK;	399	return CAN_OK;
400	}	400	}
401	}	401	}
402	else if (rxBuffer == 1) {	402	else if (rxBuffer == 1) {
403	/* check BUF1 */	403	/* check BUF1 */
404	if (stat & MCP_STAT_RX1IF) {	404	if (stat & MCP_STAT_RX1IF) {
405	/* Msg in Buffer 1 */	405	/* Msg in Buffer 1 */
406	MCP2515_ReadCanMsg(MCP_RXBUF_1, msg);	406	MCP2515_ReadCanMsg(MCP_RXBUF_1, msg);
407	MCP2515_ModifyRegister(MCP_CANINTF, MCP_RX1IF, 0);	407	MCP2515_ModifyRegister(MCP_CANINTF, MCP_RX1IF, 0);
408	return CAN_OK;	408	return CAN_OK;
409	}	409	}
410	}	410	}
411	else {	411	else {
412	/* invalid parameters */	412	/* invalid parameters */
413	return CAN_FAIL;	413	return CAN_FAIL;
414	}	414	}
415	return CAN_NO_MSG_AVAILABLE;	415	return CAN_NO_MSG_AVAILABLE;
416	#endif	416	#endif
417	}	417	}
418		418
419		419
420	/**	420	/**
421	* Checks how many messages are available in the CAN controller hardware.	421	* Checks how many messages are available in the CAN controller hardware.
422	*	422	*
423	* @return	423	* @return
424	* The number of messages available (0 if none).	424	* The number of messages available (0 if none).
425	*/	425	*/
426	static uint8_t Can_MessagesAvailableInController() {	426	static uint8_t Can_MessagesAvailableInController() {
427	#if CAN_CONTROLLER == CAN_CONTROLLER_NULL	427	#if CAN_CONTROLLER == CAN_CONTROLLER_NULL
428	/*	428	/*
429	* Check for messages in null device.	429	* Check for messages in null device.
430	*/	430	*/
431	return 0;	431	return 0;
432	#endif	432	#endif
433		433
434	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515	434	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
435	/*	435	/*
436	* Check for message in MCP2515 device.	436	* Check for message in MCP2515 device.
437	*/	437	*/
438	uint8_t res;	438	uint8_t res;
439	res = MCP2515_ReadStatus(); /* RXnIF in Bit 1 and 0 */	439	res = MCP2515_ReadStatus(); /* RXnIF in Bit 1 and 0 */
440	if (res & MCP_STAT_RXIF_MASK) {	440	if (res & MCP_STAT_RXIF_MASK) {
441	//TODO: check how many messages are available	441	//TODO: check how many messages are available
442	return 1; /* at least one message available */	442	return 1; /* at least one message available */
443	}	443	}
444	else {	444	else {
445	return 0; /* no messages available */	445	return 0; /* no messages available */
446	}	446	}
447	#endif	447	#endif
448		448
449	return 0;	449	return 0;
450	}	450	}
451		451
452		452
453	/*	453	/*
454	* Checks Controller-Error-State.	454	* Checks Controller-Error-State.
455	*	455	*
456	* @return	456	* @return
457	* CAN_OK if the controller is OK.	457	* CAN_OK if the controller is OK.
458	* CAN_FAIL if errors have occured.	458	* CAN_FAIL if errors have occured.
459	*	459	*
460	* @todo	460	* @todo
461	* Styr upp denna funktion lite b�ttre.	461	* Styr upp denna funktion lite b�ttre.
462	*/	462	*/
463	static Can_Return_t Can_ControllerCheckError() {	463	static Can_Return_t Can_ControllerCheckError() {
464	#if CAN_CONTROLLER == CAN_CONTROLLER_NULL	464	#if CAN_CONTROLLER == CAN_CONTROLLER_NULL
465	/*	465	/*
466	* Check for errors in null device.	466	* Check for errors in null device.
467	*/	467	*/
468	return CAN_OK;	468	return CAN_OK;
469	#endif	469	#endif
470		470
471	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515	471	#if CAN_CONTROLLER == CAN_CONTROLLER_MCP2515
472	/*	472	/*
473	* Check for errors in MCP2515 device.	473	* Check for errors in MCP2515 device.
474	*/	474	*/
475	uint8_t eflg = MCP2515_ReadRegister(MCP_EFLG);	475	uint8_t eflg = MCP2515_ReadRegister(MCP_EFLG);
476	if (eflg & MCP_EFLG_ERRORMASK) {	476	if (eflg & MCP_EFLG_ERRORMASK) {
477	return CAN_FAIL; /* errors found */	477	return CAN_FAIL; /* errors found */
478	}	478	}
479	else {	479	else {
480	return CAN_OK; /* no errors found */	480	return CAN_OK; /* no errors found */
481	}	481	}
482	#endif	482	#endif
483	}	483	}
484		484
485		485
486	#if (CAN_QUEUE_SIZE_TX > 0) \|\| (CAN_QUEUE_SIZE_RX > 0)	486	#if (CAN_QUEUE_SIZE_TX > 0) \|\| (CAN_QUEUE_SIZE_RX > 0)
487	/**	487	/**
488	* Initializes a CAN queue.	488	* Initializes a CAN queue.
489	*	489	*
490	* @param q	490	* @param q
491	* Pointer to the queue object.	491	* Pointer to the queue object.
492	*	492	*
493	* @param size	493	* @param size
494	* Size of the queue (number of messages that can be queued).	494	* Size of the queue (number of messages that can be queued).
495	*	495	*
496	* @param dataPtr	496	* @param dataPtr
497	* Pointer to the message storage buffer that should be used by the queue.	497	* Pointer to the message storage buffer that should be used by the queue.
498	*/	498	*/
499	static void Can_QueueInit(Can_MessageQueue_t q, uint8_t size, Can_Message_t dataPtr) {	499	static void Can_QueueInit(Can_MessageQueue_t q, uint8_t size, Can_Message_t dataPtr) {
500	q->dataPtr = dataPtr;	500	q->dataPtr = dataPtr;

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