File content as of revision 0:f5d099885d3d:

/* seeed_can_spi.cpp
 * 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.
 */
 
#include "seeed_can_spi.h"

/** reset the MCP2515
 */
void mcpReset(can_t *obj)
{
    obj->ncs = 0;
    obj->spi.write(MCP_RESET);
    obj->ncs = 1;
    wait_ms(10);
}

/** read from a single MCP2515 register
 */
uint8_t mcpRead(can_t *obj, const uint8_t address)
{
    uint8_t result;

    obj->ncs = 0;
    obj->spi.write(MCP_READ);
    obj->spi.write(address);
    result = obj->spi.write(0x00);
    obj->ncs = 1;
    return result;
}

/** read multiple MCP2515 registers sequentially into an array (relies on address auto-increment)
 */
void mcpReadMultiple(can_t *obj, const uint8_t address, uint8_t values[], const uint8_t n)
{
    obj->ncs = 0;
    obj->spi.write(MCP_READ);
    obj->spi.write(address);
    for (uint32_t i=0; i<n; i++) {
        values[i] = obj->spi.write(0x00);
    }
    obj->ncs = 1;
}

/** read the specified MCP2515 receive buffer into an array (needs one fewer SPI transfer than mcpReadMultiple)
 */
void mcpReadBuffer(can_t *obj, const uint8_t command, uint8_t values[], const uint8_t n)
{
    obj->ncs = 0;
    obj->spi.write(command);
    for (uint32_t i=0; i<n; i++) {
        values[i] = obj->spi.write(0x00);
    }
    obj->ncs = 1;
}

/**  write to a single MCP2515 register
 */
void mcpWrite(can_t *obj, const uint8_t address, const uint8_t value)
{
    obj->ncs = 0;
    obj->spi.write(MCP_WRITE);
    obj->spi.write(address);
    obj->spi.write(value);
    obj->ncs = 1;
}

/** write to multiple MCP2515 registers consecutively from an array
 */
void mcpWriteMultiple(can_t *obj, const uint8_t address, const uint8_t values[], const uint8_t n)
{
    obj->ncs = 0;
    obj->spi.write(MCP_WRITE);
    obj->spi.write(address);
    for (uint32_t i=0; i<n; i++) {
        obj->spi.write(values[i]);
    }
    obj->ncs = 1;
}

/** write to the specified MCP2515 transmit buffer from an array (needs one fewer SPI transfer than mcpWriteMultiple)
 */
void mcpWriteBuffer(can_t *obj, const uint8_t command, uint8_t values[], const uint8_t n)
{
    obj->ncs = 0;
    obj->spi.write(command);
    for (uint32_t i=0; i<n; i++) {
        obj->spi.write(values[i]);
    }
    obj->ncs = 1;
}

/** initiate transmission of the specified MCP2515 transmit buffer
 */
void mcpBufferRTS(can_t *obj, const uint8_t command)
{
    obj->ncs = 0;
    obj->spi.write(command);
    obj->ncs = 1;
}

/**  read mcp2515's status register
 */
uint8_t mcpStatus(can_t *obj)
{
    uint8_t status;

    obj->ncs = 0;
    obj->spi.write(MCP_READ_STATUS);
    status = obj->spi.write(0x00);
    obj->ncs = 1;
    return status;
}

/**  read mcp2515's receive status register
 */
uint8_t mcpReceiveStatus(can_t *obj)
{
    uint8_t status;

    obj->ncs = 0;
    obj->spi.write(MCP_RX_STATUS);
    status = obj->spi.write(0x00);
    obj->ncs = 1;
    return status;
}

/** modify bits of a register specified by a mask
 */
void mcpBitModify(can_t *obj, const uint8_t address, const uint8_t mask, const uint8_t data)
{
    obj->ncs = 0;
    obj->spi.write(MCP_BITMOD);
    obj->spi.write(address);
    obj->spi.write(mask);
    obj->spi.write(data);
    obj->ncs = 1;
}