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/* seeed_can_api.h
 * Copyright (c) 2013 Sophie Dexter
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef _SEEED_CAN_API_H_
#define _SEEED_CAN_API_H_

#include "seeed_can_spi.h"

// print debug information...
//#define DEBUG

#ifdef __cplusplus
extern "C" {
#endif

/** CAN driver typedefs
 */

// The 'MCP_xyz' structs mimic MCP register organisations
// A union of the struct and a simple array can be used to:
//  Process and manipulate the struct in an ordered way
//  Copy the struct to/from the MCP2512 as an array

/// Type definition to hold an MCP2515 Timing Register set structure
    struct MCP_CANtiming {
        uint8_t phseg2    : 3;      // PS2 length bits 2..0 (PHSEG2 + 1) Tq (minimum valid setting is 2 Tq)
        uint8_t reserved1 : 3;      // Unused bits (read as '0')
        uint8_t wakfil    : 1;      // Wake-up filter enable bit (1 = enabled, 0 = disabled)
        uint8_t sof       : 1;      // Start of frame bit (1 = CLKOUT pin is SOF, 0 = CLKOUT is clock)
        uint8_t prseg     : 3;      // Propagation Segment length bits 2..0 (PRSEG + 1) Tq (minimum valid setting is 1 Tq)
        uint8_t phseg1    : 3;      // PS2 length bits 2..0 (PRSEG + 1) Tq (minimum valid setting is 1 Tq)
        uint8_t sam       : 1;      // Sample Point Configuration bit (1 = Bus line is sampled 3 times, 0 = sampled once)
        uint8_t btlmode   : 1;      // PS2 Bit Time Length (1 = determined by phseg2, 0 = greater of PS1 an IPT (2 Tq))
        uint8_t brp       : 6;      // Baud Rate Prescaler bits 5..0 (Tq = 2 x (BRP + 1) / Fosc)
        uint8_t sjw       : 2;      // Synchronisation Jump Width Length bits 1..0 ((SJW + 1) Tq)
    };
    typedef struct MCP_CANtiming CANtiming;

/// Type definition to hold an MCP2515 CAN id structure
    struct MCP_CANid {
        uint8_t sid10_3   : 8;      // Bits 10..3 of a standard identifier
        uint8_t eid17_16  : 2;      // Bits 17..16 of an extended identifier
        uint8_t reserved1 : 1;      // Unused bit in RXBbSIDL
        uint8_t ide       : 1;      // Extended Identifier Flag
        // CANformat 'type'
        uint8_t srtr      : 1;      // Standard Frame Remote Transmit Request Bit (valid when IDE = 0)
        // CANtype 'type'
        // Unimplimented  in TXBnSIDL, filters and acceptance masks
        uint8_t sid2_0    : 3;      // Bits 2..0 of a standard identifier
        uint8_t eid15_8   : 8;      // Bits 15..8 of an extended identifier
        uint8_t eid7_0    : 8;      // Bits 7..0 of an extended identifier
    };
    typedef struct MCP_CANid CANid;

/// Type definition to hold an MCP2515 CAN id structure
    struct MCP_CANMsg {
        CANid id;
        uint8_t dlc       : 4;      // Bits 3..0: DLC - Data Length Counter
        uint8_t reserved1 : 2;      // unused bits in RXBnDLC
        uint8_t ertr      : 1;      // Extended Frame Remote Transmit Request Bit (valid when IDE = 1)
        // CANtype 'type'
        uint8_t reserved2 : 1;      // unused bit in RXBnDLC
        uint8_t data[8];            // CAN Message Data Bytes 0-7
    };
    typedef struct MCP_CANMsg CANMsg;

    enum CANFormat {
        CANStandard = 0,
        CANExtended = 1
    };
    typedef enum CANFormat CANFormat;

    enum CANType {
        CANData   = 0,
        CANRemote = 1
    };
    typedef enum CANType CANType;

    struct CAN_Message {
        unsigned int   id;          // 11 or 29 bit identifier
        unsigned char  data[8];     // Data field
        unsigned char  len;         // Length of data field in bytes
        CANFormat      format;      // 0 - STANDARD, 1- EXTENDED IDENTIFIER
        CANType        type;        // 0 - DATA FRAME, 1 - REMOTE FRAME
    };
    typedef struct CAN_Message CAN_Message;
    
    enum MCP_Mode {
        _NORMAL,
        _SLEEP,
        _LOOPBACK,
        _MONITOR,
        _CONFIG,
        _RESET,
    };
    typedef MCP_Mode CANMode;

/** CAN driver functions
 */
    uint8_t mcpInit(can_t *obj, const uint32_t bitRate);                // Initialise the MCP2515 and set the bit rate
    uint8_t mcpSetMode(can_t *obj, const uint8_t newmode);              // set the MCP2515's operation mode
    uint8_t mcpSetBitRate(can_t *obj, const uint32_t bitRate);          // set bitrate
    
    void mcpWriteId(can_t *obj,                                         // write a CAN id
                    const uint8_t mcp_addr,
                    const uint8_t ext,
                    const uint32_t id );
    uint8_t mcpCanRead(can_t *obj, CAN_Message *msg);                   // read a CAN message
    uint8_t mcpCanWrite(can_t *obj, CAN_Message msg);                   // write a CAN message
    
    uint8_t mcpInitMask(can_t *obj, uint8_t num, uint32_t ulData, bool ext);  // initialise an Acceptance Mask
    uint8_t mcpInitFilter(can_t *obj, uint8_t num, uint32_t ulData, bool ext);  // initialise an Acceptance Filter

    uint8_t mcpReceptionErrorCount(can_t *obj);                         // number of message reception errors
    uint8_t mcpTransmissionErrorCount(can_t *obj);                      // number of message transmission errors

    void mcpMonitor(can_t *obj, const bool silent);                     // Select between monitor (silent = 1) and normal (silent = 0) modes
    uint8_t mcpMode(can_t *obj, const CANMode mode);                    // Change CAN operation to the specified mode

#ifdef __cplusplus
};
#endif

#endif    // SEEED_CAN_API_H