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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 59 | jimmy | 1 | /** |
| 2 | * CAN Interface. This is a general high-level interface for CAN communication. |
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| 3 | * Underlying CAN controllers are abstracted by this interface, so the |
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| 4 | * application needs not work directly against the CAN controllers. |
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| 5 | * |
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| 127 | jimmy | 6 | * @date 2006-11-19 |
| 59 | jimmy | 7 | * |
| 8 | * @author Jimmy Myhrman |
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| 9 | * @author Martin Thomas |
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| 10 | * |
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| 11 | */ |
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| 12 | |||
| 13 | /*----------------------------------------------------------------------------- |
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| 14 | * Includes |
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| 15 | *---------------------------------------------------------------------------*/ |
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| 16 | #include <string.h> |
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| 17 | #include <can.h> |
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| 18 | #include "timebase.h" |
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| 19 | |||
| 20 | |||
| 21 | #ifdef CAN_CONTROLLER_MCP2515 |
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| 22 | #include "mcp2515.h" |
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| 23 | #else |
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| 24 | #error No CAN controller specified! Edit can_cfg.h ! |
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| 25 | #endif |
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| 26 | |||
| 27 | |||
| 28 | /*----------------------------------------------------------------------------- |
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| 29 | * Functions |
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| 30 | *---------------------------------------------------------------------------*/ |
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| 31 | |||
| 32 | /** |
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| 127 | jimmy | 33 | * Initializes the CAN interface. Edit can_cfg.h to choose bitrate. |
| 59 | jimmy | 34 | * |
| 35 | * @return |
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| 36 | * CAN_OK if initialization was successful. |
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| 37 | * CAN_FAILINIT otherwise. |
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| 38 | */ |
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| 127 | jimmy | 39 | Can_Return_t Can_Init() { |
| 40 | Can_Bitrate_t bitrate = CAN_BITRATE; |
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| 59 | jimmy | 41 | #ifdef CAN_CONTROLLER_MCP2515 |
| 127 | jimmy | 42 | if (MCP2515_Init(bitrate) != MCP2515_OK) { |
| 59 | jimmy | 43 | return CAN_FAILINIT; |
| 44 | } |
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| 127 | jimmy | 45 | if (MCP2515_SetCanCtrlMode(MODE_NORMAL) != MCP2515_OK) { |
| 59 | jimmy | 46 | return CAN_FAILINIT; |
| 47 | } |
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| 48 | return CAN_OK; |
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| 49 | #endif |
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| 50 | |||
| 51 | return CAN_FAILINIT; |
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| 52 | |||
| 53 | } |
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| 54 | |||
| 55 | |||
| 56 | /** |
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| 57 | * Sends a CAN message. If the CAN controller is busy, the message will be |
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| 58 | * copied to an internal transmission queue and transmitted later. |
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| 59 | * |
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| 60 | * @param msg |
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| 61 | * Pointer to the CAN message storage buffer. |
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| 62 | * @return |
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| 63 | * CAN_OK if the message was successfully sent (or put in queue). |
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| 64 | * CAN_FAILTX if the controller is busy AND the transmission queue is full. |
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| 65 | */ |
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| 127 | jimmy | 66 | Can_Return_t Can_Send(Can_Message_t* msg) { |
| 59 | jimmy | 67 | |
| 68 | #ifdef CAN_CONTROLLER_MCP2515 |
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| 69 | uint8_t res, txbuf_n; |
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| 127 | jimmy | 70 | res = MCP2515_GetNextFreeTXBuf(&txbuf_n); // info = addr. |
| 59 | jimmy | 71 | if (res == MCP_ALLTXBUSY) { |
| 72 | return CAN_FAILTX; |
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| 73 | } |
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| 127 | jimmy | 74 | MCP2515_WriteCanMsg(txbuf_n, msg); |
| 75 | MCP2515_StartTransmit(txbuf_n); |
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| 59 | jimmy | 76 | return CAN_OK; |
| 77 | #endif |
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| 78 | |||
| 79 | } |
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| 80 | |||
| 81 | |||
| 82 | /** |
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| 83 | * Pulls a message from the internal CAN interface reception queue. Unless this queue |
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| 84 | * is empty, a CAN message is moved from the queue into the message storage provided |
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| 85 | * by the calling function. |
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| 86 | * |
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| 87 | * @param msg |
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| 88 | * Pointer to the message storage buffer. |
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| 89 | * @return |
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| 90 | * CAN_OK if a received message was successfully copied into the buffer. |
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| 91 | * CAN_NOMSG if there are no received messages available. |
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| 92 | */ |
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| 127 | jimmy | 93 | Can_Return_t Can_Receive(Can_Message_t *msg) { |
| 59 | jimmy | 94 | |
| 95 | #ifdef CAN_CONTROLLER_MCP2515 |
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| 96 | uint8_t stat, res; |
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| 127 | jimmy | 97 | stat = MCP2515_ReadStatus(); |
| 59 | jimmy | 98 | if (stat & MCP_STAT_RX0IF) { |
| 99 | // Msg in Buffer 0 |
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| 127 | jimmy | 100 | MCP2515_ReadCanMsg( MCP_RXBUF_0, msg); |
| 101 | MCP2515_ModifyRegister(MCP_CANINTF, MCP_RX0IF, 0); |
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| 59 | jimmy | 102 | res = CAN_OK; |
| 103 | } |
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| 104 | else if (stat & MCP_STAT_RX1IF) { |
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| 105 | // Msg in Buffer 1 |
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| 127 | jimmy | 106 | MCP2515_ReadCanMsg( MCP_RXBUF_1, msg); |
| 107 | MCP2515_ModifyRegister(MCP_CANINTF, MCP_RX1IF, 0); |
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| 59 | jimmy | 108 | res = CAN_OK; |
| 109 | } |
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| 110 | else { |
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| 111 | res = CAN_NOMSG; |
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| 112 | } |
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| 113 | return res; |
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| 114 | #endif |
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| 115 | |||
| 116 | } |
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| 117 | |||
| 118 | |||
| 119 | /** |
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| 120 | * Checks if there are any received CAN messages waiting in the reception queue. |
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| 121 | * |
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| 122 | * @return |
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| 123 | * CAN_MSGAVAIL if there are messages available. |
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| 124 | * CAN_NOMSG if the queue is empty. |
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| 125 | */ |
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| 127 | jimmy | 126 | Can_Return_t Can_ReceiveAvailable(void) { |
| 59 | jimmy | 127 | |
| 128 | #ifdef CAN_CONTROLLER_MCP2515 |
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| 129 | uint8_t res; |
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| 127 | jimmy | 130 | res = MCP2515_ReadStatus(); // RXnIF in Bit 1 and 0 |
| 59 | jimmy | 131 | if ( res & MCP_STAT_RXIF_MASK ) { |
| 132 | return CAN_MSGAVAIL; |
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| 133 | } |
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| 134 | else { |
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| 135 | return CAN_NOMSG; |
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| 136 | } |
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| 137 | #endif |
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| 138 | |||
| 139 | } |
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| 140 | |||
| 141 | |||
| 142 | /* |
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| 143 | * Checks Controller-Error-State. |
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| 144 | * |
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| 145 | * @return |
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| 146 | * CAN_OK if the controller is OK. |
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| 147 | * CAN_CTRLERROR if errors have occured. |
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| 148 | * @todo |
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| 149 | * Styr upp denna funktion lite bättre. |
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| 150 | */ |
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| 127 | jimmy | 151 | Can_Return_t Can_CheckError(void) { |
| 59 | jimmy | 152 | |
| 153 | #ifdef CAN_CONTROLLER_MCP2515 |
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| 127 | jimmy | 154 | uint8_t eflg = MCP2515_ReadRegister(MCP_EFLG); |
| 59 | jimmy | 155 | if (eflg & MCP_EFLG_ERRORMASK) { |
| 156 | return CAN_CTRLERROR; |
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| 157 | } |
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| 158 | else { |
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| 159 | return CAN_OK; |
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| 160 | } |
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| 161 | #endif |
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| 162 | |||
| 163 | } |