C/C++ - CAN Bricklet 2.0

This is the description of the C/C++ API bindings for the CAN Bricklet 2.0. General information and technical specifications for the CAN Bricklet 2.0 are summarized in its hardware description.

An installation guide for the C/C++ API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Loopback

Download (example_loopback.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_can_v2.h"

#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your CAN Bricklet 2.0

// Callback function for frame read callback
void cb_frame_read(uint8_t frame_type, uint32_t identifier,
                   uint8_t *data, uint16_t data_length, void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("Frame Type: %u\n", frame_type);
    printf("Identifier: %u\n", identifier);
    printf("Data (Length: %d):", data_length);

    uint8_t i;
    for (i = 0; i < data_length && i < 8; ++i) {
        printf(" %d", data[i]);
    }

    printf("\n");
    printf("\n");
}

int main(void) {
    // Create IP connection
    IPConnection ipcon;
    ipcon_create(&ipcon);

    // Create device object
    CANV2 can;
    can_v2_create(&can, UID, &ipcon);

    // Connect to brickd
    if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
        fprintf(stderr, "Could not connect\n");
        return 1;
    }
    // Don't use device before ipcon is connected

    // Configure transceiver for loopback mode
    can_v2_set_transceiver_configuration(&can, 1000000, 625,
                                         CAN_V2_TRANSCEIVER_MODE_LOOPBACK);

    // Register frame read callback to function cb_frame_read
    can_v2_register_callback(&can,
                             CAN_V2_CALLBACK_FRAME_READ,
                             (void *)cb_frame_read,
                             NULL);

    // Enable frame read callback
    can_v2_set_frame_read_callback_configuration(&can, true);

    // Write standard data frame with identifier 1742 and 3 bytes of data
    uint8_t data[3] = {42, 23, 17};
    bool success;
    can_v2_write_frame(&can, CAN_V2_FRAME_TYPE_STANDARD_DATA, 1742, data, 3, &success);

    printf("Press key to exit\n");
    getchar();
    can_v2_set_frame_read_callback_configuration(&can, false);
    can_v2_destroy(&can);
    ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
    return 0;
}

API

Every function of the C/C++ bindings returns an integer which describes an error code. Data returned from the device, when a getter is called, is handled via call by reference. These parameters are labeled with the ret_ prefix.

Possible error codes are:

  • E_OK = 0
  • E_TIMEOUT = -1
  • E_NO_STREAM_SOCKET = -2
  • E_HOSTNAME_INVALID = -3
  • E_NO_CONNECT = -4
  • E_NO_THREAD = -5
  • E_NOT_ADDED = -6 (unused since bindings version 2.0.0)
  • E_ALREADY_CONNECTED = -7
  • E_NOT_CONNECTED = -8
  • E_INVALID_PARAMETER = -9
  • E_NOT_SUPPORTED = -10
  • E_UNKNOWN_ERROR_CODE = -11
  • E_STREAM_OUT_OF_SYNC = -12

as defined in ip_connection.h.

All functions listed below are thread-safe.

Basic Functions

void can_v2_create(CANV2 *can_v2, const char *uid, IPConnection *ipcon)

Creates the device object can_v2 with the unique device ID uid and adds it to the IPConnection ipcon:

CANV2 can_v2;
can_v2_create(&can_v2, "YOUR_DEVICE_UID", &ipcon);

This device object can be used after the IP connection has been connected (see examples above).

void can_v2_destroy(CANV2 *can_v2)

Removes the device object can_v2 from its IPConnection and destroys it. The device object cannot be used anymore afterwards.

int can_v2_write_frame(CANV2 *can_v2, uint8_t frame_type, uint32_t identifier, uint8_t *data, uint8_t data_length, bool *ret_success)

Writes a data or remote frame to the write queue to be transmitted over the CAN transceiver.

The Bricklet supports the standard 11-bit (CAN 2.0A) and the additional extended 29-bit (CAN 2.0B) identifiers. For standard frames the Bricklet uses bit 0 to 10 from the identifier parameter as standard 11-bit identifier. For extended frames the Bricklet uses bit 0 to 28 from the identifier parameter as extended 29-bit identifier.

The data parameter can be up to 15 bytes long. For data frames up to 8 bytes will be used as the actual data. The length (DLC) field in the data or remote frame will be set to the actual length of the data parameter. This allows to transmit data and remote frames with excess length. For remote frames only the length of the data parameter is used. The actual data bytes are ignored.

Returns true if the frame was successfully added to the write queue. Returns false if the frame could not be added because write queue is already full or because the write buffer or the write backlog are configured with a size of zero (see can_v2_set_queue_configuration()).

The write queue can overflow if frames are written to it at a higher rate than the Bricklet can transmitted them over the CAN transceiver. This may happen if the CAN transceiver is configured as read-only or is using a low baud rate (see can_v2_set_transceiver_configuration()). It can also happen if the CAN bus is congested and the frame cannot be transmitted because it constantly loses arbitration or because the CAN transceiver is currently disabled due to a high write error level (see can_v2_get_error_log()).

The following defines are available for this function:

  • CAN_V2_FRAME_TYPE_STANDARD_DATA = 0
  • CAN_V2_FRAME_TYPE_STANDARD_REMOTE = 1
  • CAN_V2_FRAME_TYPE_EXTENDED_DATA = 2
  • CAN_V2_FRAME_TYPE_EXTENDED_REMOTE = 3
int can_v2_read_frame(CANV2 *can_v2, bool *ret_success, uint8_t *ret_frame_type, uint32_t *ret_identifier, uint8_t *ret_data, uint8_t *ret_data_length)

Tries to read the next data or remote frame from the read queue and returns it. If a frame was successfully read, then the success return value is set to true and the other return values contain the frame. If the read queue is empty and no frame could be read, then the success return value is set to false and the other return values contain invalid data.

The identifier return value follows the identifier format described for can_v2_write_frame().

The data return value can be up to 15 bytes long. For data frames up to the first 8 bytes are the actual received data. All bytes after the 8th byte are always zero and only there to indicate the length of a data or remote frame with excess length. For remote frames the length of the data return value represents the requested length. The actual data bytes are always zero.

A configurable read filter can be used to define which frames should be received by the CAN transceiver and put into the read queue (see can_v2_set_read_filter_configuration()).

Instead of polling with this function, you can also use callbacks. See the can_v2_set_frame_read_callback_configuration() function and the CAN_V2_CALLBACK_FRAME_READ callback.

The following defines are available for this function:

  • CAN_V2_FRAME_TYPE_STANDARD_DATA = 0
  • CAN_V2_FRAME_TYPE_STANDARD_REMOTE = 1
  • CAN_V2_FRAME_TYPE_EXTENDED_DATA = 2
  • CAN_V2_FRAME_TYPE_EXTENDED_REMOTE = 3
int can_v2_set_transceiver_configuration(CANV2 *can_v2, uint32_t baud_rate, uint16_t sample_point, uint8_t transceiver_mode)

Sets the transceiver configuration for the CAN bus communication.

The baud rate can be configured in bit/s between 10 and 1000 kbit/s and the sample point can be configured in 1/10 % between 50 and 90 %.

The CAN transceiver has three different modes:

  • Normal: Reads from and writes to the CAN bus and performs active bus error detection and acknowledgement.
  • Loopback: All reads and writes are performed internally. The transceiver is disconnected from the actual CAN bus.
  • Read-Only: Only reads from the CAN bus, but does neither active bus error detection nor acknowledgement. Only the receiving part of the transceiver is connected to the CAN bus.

The default is: 125 kbit/s, 62.5 % and normal transceiver mode.

The following defines are available for this function:

  • CAN_V2_TRANSCEIVER_MODE_NORMAL = 0
  • CAN_V2_TRANSCEIVER_MODE_LOOPBACK = 1
  • CAN_V2_TRANSCEIVER_MODE_READ_ONLY = 2
int can_v2_get_transceiver_configuration(CANV2 *can_v2, uint32_t *ret_baud_rate, uint16_t *ret_sample_point, uint8_t *ret_transceiver_mode)

Returns the configuration as set by can_v2_set_transceiver_configuration().

The following defines are available for this function:

  • CAN_V2_TRANSCEIVER_MODE_NORMAL = 0
  • CAN_V2_TRANSCEIVER_MODE_LOOPBACK = 1
  • CAN_V2_TRANSCEIVER_MODE_READ_ONLY = 2

Advanced Functions

int can_v2_set_queue_configuration(CANV2 *can_v2, uint8_t write_buffer_size, int32_t write_buffer_timeout, uint16_t write_backlog_size, int8_t *read_buffer_sizes, uint8_t read_buffer_sizes_length, uint16_t read_backlog_size)

Sets the write and read queue configuration.

The CAN transceiver has 32 buffers in total in hardware for transmitting and receiving frames. Additionally, the Bricklet has a backlog for 768 frames in total in software. The buffers and the backlog can be freely assigned to the write and read queues.

can_v2_write_frame() writes a frame into the write backlog. The Bricklet moves the frame from the backlog into a free write buffer. The CAN transceiver then transmits the frame from the write buffer to the CAN bus. If there are no write buffers (write_buffer_size is zero) or there is no write backlog (write_backlog_size is zero) then no frames can be transmitted and can_v2_write_frame() returns always false.

The CAN transceiver receives a frame from the CAN bus and stores it into a free read buffer. The Bricklet moves the frame from the read buffer into the read backlog. can_v2_read_frame() reads the frame from the read backlog and returns it. If there are no read buffers (read_buffer_sizes is empty) or there is no read backlog (read_backlog_size is zero) then no frames can be received and can_v2_read_frame() returns always false.

There can be multiple read buffers, because the CAN transceiver cannot receive data and remote frames into the same read buffer. A positive read buffer size represents a data frame read buffer and a negative read buffer size represents a remote frame read buffer. A read buffer size of zero is not allowed. By default the first read buffer is configured for data frames and the second read buffer is configured for remote frame. There can be up to 32 different read buffers, assuming that no write buffer is used. Each read buffer has its own filter configuration (see can_v2_set_read_filter_configuration()).

A valid queue configuration fulfills these conditions:

write_buffer_size + read_buffer_size_0 + read_buffer_size_1 + ... + read_buffer_size_31 <= 32
write_backlog_size + read_backlog_size <= 768

The write buffer timeout has three different modes that define how a failed frame transmission should be handled:

  • Single-Shot (< 0): Only one transmission attempt will be made. If the transmission fails then the frame is discarded.
  • Infinite (= 0): Infinite transmission attempts will be made. The frame will never be discarded.
  • Milliseconds (> 0): A limited number of transmission attempts will be made. If the frame could not be transmitted successfully after the configured number of milliseconds then the frame is discarded.

The current content of the queues is lost when this function is called.

The default is:

  • 8 write buffers,
  • infinite write timeout,
  • 383 write backlog frames,
  • 16 read buffers for data frames,
  • 8 read buffers for remote frames and
  • 383 read backlog frames.
int can_v2_get_queue_configuration(CANV2 *can_v2, uint8_t *ret_write_buffer_size, int32_t *ret_write_buffer_timeout, uint16_t *ret_write_backlog_size, int8_t *ret_read_buffer_sizes, uint8_t *ret_read_buffer_sizes_length, uint16_t *ret_read_backlog_size)

Returns the queue configuration as set by can_v2_set_queue_configuration().

int can_v2_set_read_filter_configuration(CANV2 *can_v2, uint8_t buffer_index, uint8_t filter_mode, uint32_t filter_mask, uint32_t filter_identifier)

Set the read filter configuration for the given read buffer index. This can be used to define which frames should be received by the CAN transceiver and put into the read buffer.

The read filter has four different modes that define if and how the filter mask and the filter identifier are applied:

  • Accept-All: All frames are received.
  • Match-Standard-Only: Only standard frames with a matching identifier are received.
  • Match-Extended-Only: Only extended frames with a matching identifier are received.
  • Match-Standard-And-Extended: Standard and extended frames with a matching identifier are received.

The filter mask and filter identifier are used as bit masks. Their usage depends on the mode:

  • Accept-All: Mask and identifier are ignored.
  • Match-Standard-Only: Bit 0 to 10 (11 bits) of filter mask and filter identifier are used to match the 11-bit identifier of standard frames.
  • Match-Extended-Only: Bit 0 to 28 (29 bits) of filter mask and filter identifier are used to match the 29-bit identifier of extended frames.
  • Match-Standard-And-Extended: Bit 18 to 28 (11 bits) of filter mask and filter identifier are used to match the 11-bit identifier of standard frames, bit 0 to 17 (18 bits) are ignored in this case. Bit 0 to 28 (29 bits) of filter mask and filter identifier are used to match the 29-bit identifier of extended frames.

The filter mask and filter identifier are applied in this way: The filter mask is used to select the frame identifier bits that should be compared to the corresponding filter identifier bits. All unselected bits are automatically accepted. All selected bits have to match the filter identifier to be accepted. If all bits for the selected mode are accepted then the frame is accepted and is added to the read buffer.

Filter Mask Bit Filter Identifier Bit Frame Identifier Bit Result
0 X X Accept
1 0 0 Accept
1 0 1 Reject
1 1 0 Reject
1 1 1 Accept

For example, to receive standard frames with identifier 0x123 only, the mode can be set to Match-Standard-Only with 0x7FF as mask and 0x123 as identifier. The mask of 0x7FF selects all 11 identifier bits for matching so that the identifier has to be exactly 0x123 to be accepted.

To accept identifier 0x123 and identifier 0x456 at the same time, just set filter 2 to 0x456 and keep mask and filter 1 unchanged.

There can be up to 32 different read filters configured at the same time, because there can be up to 32 read buffer (see can_v2_set_queue_configuration()).

The default mode is accept-all for all read buffers.

The following defines are available for this function:

  • CAN_V2_FILTER_MODE_ACCEPT_ALL = 0
  • CAN_V2_FILTER_MODE_MATCH_STANDARD_ONLY = 1
  • CAN_V2_FILTER_MODE_MATCH_EXTENDED_ONLY = 2
  • CAN_V2_FILTER_MODE_MATCH_STANDARD_AND_EXTENDED = 3
int can_v2_get_read_filter_configuration(CANV2 *can_v2, uint8_t buffer_index, uint8_t *ret_filter_mode, uint32_t *ret_filter_mask, uint32_t *ret_filter_identifier)

Returns the read filter configuration as set by can_v2_set_read_filter_configuration().

The following defines are available for this function:

  • CAN_V2_FILTER_MODE_ACCEPT_ALL = 0
  • CAN_V2_FILTER_MODE_MATCH_STANDARD_ONLY = 1
  • CAN_V2_FILTER_MODE_MATCH_EXTENDED_ONLY = 2
  • CAN_V2_FILTER_MODE_MATCH_STANDARD_AND_EXTENDED = 3
int can_v2_get_error_log(CANV2 *can_v2, uint8_t *ret_transceiver_state, uint8_t *ret_transceiver_write_error_level, uint8_t *ret_transceiver_read_error_level, uint32_t *ret_transceiver_stuffing_error_count, uint32_t *ret_transceiver_format_error_count, uint32_t *ret_transceiver_ack_error_count, uint32_t *ret_transceiver_bit1_error_count, uint32_t *ret_transceiver_bit0_error_count, uint32_t *ret_transceiver_crc_error_count, uint32_t *ret_write_buffer_timeout_error_count, uint32_t *ret_read_buffer_overflow_error_count, bool *ret_read_buffer_overflow_error_occurred, uint8_t *ret_read_buffer_overflow_error_occurred_length, uint32_t *ret_read_backlog_overflow_error_count)

Returns information about different kinds of errors.

The write and read error levels indicate the current level of stuffing, form, acknowledgement, bit and checksum errors during CAN bus write and read operations. For each of this error kinds there is also an individual counter.

When the write error level extends 255 then the CAN transceiver gets disabled and no frames can be transmitted or received anymore. The CAN transceiver will automatically be activated again after the CAN bus is idle for a while.

The write buffer timeout, read buffer and backlog overflow counts represents the number of these errors:

  • A write buffer timeout occurs if a frame could not be transmitted before the configured write buffer timeout expired (see can_v2_set_queue_configuration()).
  • A read buffer overflow occurs if a read buffer of the CAN transceiver still contains the last received frame when the next frame arrives. In this case the last received frame is lost. This happens if the CAN transceiver receives more frames than the Bricklet can handle. Using the read filter (see can_v2_set_read_filter_configuration()) can help to reduce the amount of received frames. This count is not exact, but a lower bound, because the Bricklet might not able detect all overflows if they occur in rapid succession.
  • A read backlog overflow occurs if the read backlog of the Bricklet is already full when the next frame should be read from a read buffer of the CAN transceiver. In this case the frame in the read buffer is lost. This happens if the CAN transceiver receives more frames to be added to the read backlog than are removed from the read backlog using the can_v2_read_frame() function. Using the CAN_V2_CALLBACK_FRAME_READ callback ensures that the read backlog can not overflow.

The read buffer overflow counter counts the overflows of all configured read buffers. Which read buffer exactly suffered from an overflow can be figured out from the read buffer overflow occurrence list (read_buffer_overflow_error_occurred).

The following defines are available for this function:

  • CAN_V2_TRANSCEIVER_STATE_ACTIVE = 0
  • CAN_V2_TRANSCEIVER_STATE_PASSIVE = 1
  • CAN_V2_TRANSCEIVER_STATE_DISABLED = 2
int can_v2_set_communication_led_config(CANV2 *can_v2, uint8_t config)

Sets the communication LED configuration. By default the LED shows CAN-Bus traffic, it flickers once for every 40 transmitted or received frames.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is off.

The following defines are available for this function:

  • CAN_V2_COMMUNICATION_LED_CONFIG_OFF = 0
  • CAN_V2_COMMUNICATION_LED_CONFIG_ON = 1
  • CAN_V2_COMMUNICATION_LED_CONFIG_SHOW_HEARTBEAT = 2
  • CAN_V2_COMMUNICATION_LED_CONFIG_SHOW_COMMUNICATION = 3
int can_v2_get_communication_led_config(CANV2 *can_v2, uint8_t *ret_config)

Returns the configuration as set by can_v2_set_communication_led_config()

The following defines are available for this function:

  • CAN_V2_COMMUNICATION_LED_CONFIG_OFF = 0
  • CAN_V2_COMMUNICATION_LED_CONFIG_ON = 1
  • CAN_V2_COMMUNICATION_LED_CONFIG_SHOW_HEARTBEAT = 2
  • CAN_V2_COMMUNICATION_LED_CONFIG_SHOW_COMMUNICATION = 3
int can_v2_set_error_led_config(CANV2 *can_v2, uint8_t config)

Sets the error LED configuration.

By default (show-transceiver-state) the error LED turns on if the CAN transceiver is passive or disabled state (see can_v2_get_error_log()). If the CAN transceiver is in active state the LED turns off.

If the LED is configured as show-error then the error LED turns on if any error occurs. If you call this function with the show-error option again, the LED will turn off until the next error occurs.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is off.

The following defines are available for this function:

  • CAN_V2_ERROR_LED_CONFIG_OFF = 0
  • CAN_V2_ERROR_LED_CONFIG_ON = 1
  • CAN_V2_ERROR_LED_CONFIG_SHOW_HEARTBEAT = 2
  • CAN_V2_ERROR_LED_CONFIG_SHOW_TRANSCEIVER_STATE = 3
  • CAN_V2_ERROR_LED_CONFIG_SHOW_ERROR = 4
int can_v2_get_error_led_config(CANV2 *can_v2, uint8_t *ret_config)

Returns the configuration as set by can_v2_set_error_led_config().

The following defines are available for this function:

  • CAN_V2_ERROR_LED_CONFIG_OFF = 0
  • CAN_V2_ERROR_LED_CONFIG_ON = 1
  • CAN_V2_ERROR_LED_CONFIG_SHOW_HEARTBEAT = 2
  • CAN_V2_ERROR_LED_CONFIG_SHOW_TRANSCEIVER_STATE = 3
  • CAN_V2_ERROR_LED_CONFIG_SHOW_ERROR = 4
int can_v2_get_api_version(CANV2 *can_v2, uint8_t ret_api_version[3])

Returns the version of the API definition (major, minor, revision) implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

int can_v2_get_response_expected(CANV2 *can_v2, uint8_t function_id, bool *ret_response_expected)

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by can_v2_set_response_expected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

See can_v2_set_response_expected() for the list of function ID defines available for this function.

int can_v2_set_response_expected(CANV2 *can_v2, uint8_t function_id, bool response_expected)

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following function ID defines are available for this function:

  • CAN_V2_FUNCTION_SET_FRAME_READ_CALLBACK_CONFIGURATION = 3
  • CAN_V2_FUNCTION_SET_TRANSCEIVER_CONFIGURATION = 5
  • CAN_V2_FUNCTION_SET_QUEUE_CONFIGURATION = 7
  • CAN_V2_FUNCTION_SET_READ_FILTER_CONFIGURATION = 9
  • CAN_V2_FUNCTION_SET_COMMUNICATION_LED_CONFIG = 12
  • CAN_V2_FUNCTION_SET_ERROR_LED_CONFIG = 14
  • CAN_V2_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • CAN_V2_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • CAN_V2_FUNCTION_RESET = 243
  • CAN_V2_FUNCTION_WRITE_UID = 248
int can_v2_set_response_expected_all(CANV2 *can_v2, bool response_expected)

Changes the response expected flag for all setter and callback configuration functions of this device at once.

int can_v2_get_spitfp_error_count(CANV2 *can_v2, uint32_t *ret_error_count_ack_checksum, uint32_t *ret_error_count_message_checksum, uint32_t *ret_error_count_frame, uint32_t *ret_error_count_overflow)

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

int can_v2_set_bootloader_mode(CANV2 *can_v2, uint8_t mode, uint8_t *ret_status)

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following defines are available for this function:

  • CAN_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • CAN_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • CAN_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • CAN_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • CAN_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • CAN_V2_BOOTLOADER_STATUS_OK = 0
  • CAN_V2_BOOTLOADER_STATUS_INVALID_MODE = 1
  • CAN_V2_BOOTLOADER_STATUS_NO_CHANGE = 2
  • CAN_V2_BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • CAN_V2_BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • CAN_V2_BOOTLOADER_STATUS_CRC_MISMATCH = 5
int can_v2_get_bootloader_mode(CANV2 *can_v2, uint8_t *ret_mode)

Returns the current bootloader mode, see can_v2_set_bootloader_mode().

The following defines are available for this function:

  • CAN_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • CAN_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • CAN_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • CAN_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • CAN_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
int can_v2_set_write_firmware_pointer(CANV2 *can_v2, uint32_t pointer)

Sets the firmware pointer for can_v2_write_firmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

int can_v2_write_firmware(CANV2 *can_v2, uint8_t data[64], uint8_t *ret_status)

Writes 64 Bytes of firmware at the position as written by can_v2_set_write_firmware_pointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

int can_v2_set_status_led_config(CANV2 *can_v2, uint8_t config)

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following defines are available for this function:

  • CAN_V2_STATUS_LED_CONFIG_OFF = 0
  • CAN_V2_STATUS_LED_CONFIG_ON = 1
  • CAN_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • CAN_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
int can_v2_get_status_led_config(CANV2 *can_v2, uint8_t *ret_config)

Returns the configuration as set by can_v2_set_status_led_config()

The following defines are available for this function:

  • CAN_V2_STATUS_LED_CONFIG_OFF = 0
  • CAN_V2_STATUS_LED_CONFIG_ON = 1
  • CAN_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • CAN_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
int can_v2_get_chip_temperature(CANV2 *can_v2, int16_t *ret_temperature)

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

int can_v2_reset(CANV2 *can_v2)

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

int can_v2_write_uid(CANV2 *can_v2, uint32_t uid)

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

int can_v2_read_uid(CANV2 *can_v2, uint32_t *ret_uid)

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

int can_v2_get_identity(CANV2 *can_v2, char ret_uid[8], char ret_connected_uid[8], char *ret_position, uint8_t ret_hardware_version[3], uint8_t ret_firmware_version[3], uint16_t *ret_device_identifier)

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c' or 'd'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

void can_v2_register_callback(CANV2 *can_v2, int16_t callback_id, void *function, void *user_data)

Registers the given function with the given callback_id. The user_data will be passed as the last parameter to the function.

The available callback IDs with corresponding function signatures are listed below.

int can_v2_set_frame_read_callback_configuration(CANV2 *can_v2, bool enabled)

Enables and disables the CAN_V2_CALLBACK_FRAME_READ callback.

By default the callback is disabled.

int can_v2_get_frame_read_callback_configuration(CANV2 *can_v2, bool *ret_enabled)

Returns true if the CAN_V2_CALLBACK_FRAME_READ callback is enabled, false otherwise.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the can_v2_register_callback() function. The parameters consist of the device object, the callback ID, the callback function and optional user data:

void my_callback(int p, void *user_data) {
    printf("parameter: %d\n", p);
}

can_v2_register_callback(&can_v2, CAN_V2_CALLBACK_EXAMPLE, (void *)my_callback, NULL);

The available constants with corresponding callback function signatures are described below.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

CAN_V2_CALLBACK_FRAME_READ
void callback(uint8_t frame_type, uint32_t identifier, uint8_t *data, uint8_t data_length, void *user_data)

This callback is triggered if a data or remote frame was received by the CAN transceiver.

The identifier return value follows the identifier format described for can_v2_write_frame().

For details on the data return value see can_v2_read_frame().

A configurable read filter can be used to define which frames should be received by the CAN transceiver and put into the read queue (see can_v2_set_queue_configuration()).

To enable this callback, use can_v2_set_frame_read_callback_configuration().

The following defines are available for this function:

  • CAN_V2_FRAME_TYPE_STANDARD_DATA = 0
  • CAN_V2_FRAME_TYPE_STANDARD_REMOTE = 1
  • CAN_V2_FRAME_TYPE_EXTENDED_DATA = 2
  • CAN_V2_FRAME_TYPE_EXTENDED_REMOTE = 3

Constants

CAN_V2_DEVICE_IDENTIFIER

This constant is used to identify a CAN Bricklet 2.0.

The can_v2_get_identity() function and the IPCON_CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

CAN_V2_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a CAN Bricklet 2.0.