CAN

CAN driver support for hardware abstraction layer.

Minimalist code

// init
rt_dev_t can = can(1);
can_open(can);
can_setBitTiming(can, 1000000, 1, 4, 2);
can_enable(can);
can_setMode(can, CAN_MODE_NORMAL);

// send and receive data
CAN_MSG_HEADER can_header;
char data[8] = {0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF};
can_header.size = 8;
can_header.id = 0x01AB45CD;
can_header.flags = CAN_VERS2BA;
can_send(can, 0, &can_header, data);

char rdata[8];
int r = can_rec(can, 0, &can_header, rdata);
if (r == 1)
{
    printf("%#08X\n", rdata);
}

API

Device assignation

can_getFreeDevice

rt_dev_t can_getFreeDevice();

Gives a free can device number and opens it

can_open

int can_open(rt_dev_t device);

Opens a can bus device

can_close

int can_close(rt_dev_t device);

Closes a can bus device

can_isOpened

bool can_isOpened(rt_dev_t device)

Gives the SDK device status

Device enable/disable

can_enable

int can_enable(rt_dev_t device);

Enables the specified can bus device

can_disable

int can_disable(rt_dev_t device);

Disables the specified can bus device

can_isEnabled

bool can_isEnabled(rt_dev_t device)

Gives the SDK enabled state

Device settings

can_setBitTiming

int can_setBitTiming(rt_dev_t device, uint32_t bitRate, uint8_t propagSeg, uint8_t s1Seg, uint8_t s2Seg);

Sets bit rate and segments timing. Sum of all segments (propagSeg + s1Seg +, s2Seg) + 1 must be contained in the range of 8 to 25 quantums.

CAN Bit Timing (8-25 Tq) segments computation :

can_bitRate

uint32_t can_bitRate(rt_dev_t device);

Gets the true bit rate

can_effectiveBitRate

uint32_t can_effectiveBitRate(rt_dev_t device);

Gets the effective bit rate

can_propagSeg

uint8_t can_propagSeg(rt_dev_t device);

Gets the current propagation segment length

can_s1Seg

uint8_t can_s1Seg(rt_dev_t device);

Gets the current S1 segment length

can_s2Seg

uint8_t can_s2Seg(rt_dev_t device);

Gets the current S2 segment length

Device read / write

can_send

int can_send(rt_dev_t device, uint8_t fifo, CAN_MSG_HEADER *header, char *data);

Puts a message in fifo fifo

can_rec

int can_rec(rt_dev_t device, uint8_t fifo, CAN_MSG_HEADER *header, char *data);

Gets a message from fifo fifo, return 1 if a message is read

Development status

Device assignation, configuration, send and read data on fifo 0 only

TODO

• multi fifo send / rec
• fifo status
• implementation on dsPIC33E/F
• interrupts

Supported architectures

Header file : can.h