C/C++ - IO-4 Bricklet 2.0

This is the description of the C/C++ API bindings for the IO-4 Bricklet 2.0. General information and technical specifications for the IO-4 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).

Output

Download (example_output.c)

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#define IPCON_EXPOSE_MILLISLEEP

#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_io4_v2.h"

#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your IO-4 Bricklet 2.0

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

    // Create device object
    IO4V2 io;
    io4_v2_create(&io, 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 channel 3 as output low
    io4_v2_set_configuration(&io, 3, 'o', false);

    // Set channel 3 alternating high/low 10 times with 100 ms delay
    int i;
    for(i = 0; i < 10; ++i) {
        millisleep(100);
        io4_v2_set_selected_value(&io, 3, true);
        millisleep(100);
        io4_v2_set_selected_value(&io, 3, false);
    }

    printf("Press key to exit\n");
    getchar();
    io4_v2_destroy(&io);
    ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
    return 0;
}

Interrupt

Download (example_interrupt.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_io4_v2.h"

#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your IO-4 Bricklet 2.0

// Callback function for input value callback
void cb_input_value(uint8_t channel, bool changed, bool value, void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("Channel: %u\n", channel);
    printf("Changed: %s\n", changed ? "true" : "false");
    printf("Value: %s\n", value ? "true" : "false");
    printf("\n");
}

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

    // Create device object
    IO4V2 io;
    io4_v2_create(&io, 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

    // Register input value callback to function cb_input_value
    io4_v2_register_callback(&io,
                             IO4_V2_CALLBACK_INPUT_VALUE,
                             (void *)cb_input_value,
                             NULL);

    // Set period for input value (channel 1) callback to 0.5s (500ms)
    io4_v2_set_input_value_callback_configuration(&io, 1, 500, false);

    printf("Press key to exit\n");
    getchar();
    io4_v2_destroy(&io);
    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 io4_v2_create(IO4V2 *io4_v2, const char *uid, IPConnection *ipcon)

Creates the device object io4_v2 with the unique device ID uid and adds it to the IPConnection ipcon:

IO4V2 io4_v2;
io4_v2_create(&io4_v2, "YOUR_DEVICE_UID", &ipcon);

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

void io4_v2_destroy(IO4V2 *io4_v2)

Removes the device object io4_v2 from its IPConnection and destroys it. The device object cannot be used anymore afterwards.

int io4_v2_set_value(IO4V2 *io4_v2, bool value[4])

Sets the output value of all four channels. A value of true or false outputs logic 1 or logic 0 respectively on the corresponding channel.

Use io4_v2_set_selected_value() to change only one output channel state.

For example: (True, True, False, False) will turn the channels 0-1 high and the channels 2-3 low.

Note

This function does nothing for channels that are configured as input. Pull-up resistors can be switched on with io4_v2_set_configuration().

int io4_v2_get_value(IO4V2 *io4_v2, bool ret_value[4])

Returns the logic levels that are currently measured on the channels. This function works if the channel is configured as input as well as if it is configured as output.

int io4_v2_set_selected_value(IO4V2 *io4_v2, uint8_t channel, bool value)

Sets the output value of a specific channel without affecting the other channels.

Note

This function does nothing for channels that are configured as input. Pull-up resistors can be switched on with io4_v2_set_configuration().

int io4_v2_set_configuration(IO4V2 *io4_v2, uint8_t channel, char direction, bool value)

Configures the value and direction of a specific channel. Possible directions are 'i' and 'o' for input and output.

If the direction is configured as output, the value is either high or low (set as true or false).

If the direction is configured as input, the value is either pull-up or default (set as true or false).

For example:

  • (0, 'i', true) will set channel 0 as input pull-up.
  • (1, 'i', false) will set channel 1 as input default (floating if nothing is connected).
  • (2, 'o', true) will set channel 2 as output high.
  • (3, 'o', false) will set channel 3 as output low.

The default configuration is input with pull-up.

The following defines are available for this function:

  • IO4_V2_DIRECTION_IN = 'i'
  • IO4_V2_DIRECTION_OUT = 'o'

Advanced Functions

int io4_v2_set_monoflop(IO4V2 *io4_v2, uint8_t channel, bool value, uint32_t time)

The first parameter is the desired state of the channel (true means output high and false means output low). The second parameter indicates the time (in ms) that the channel should hold the state.

If this function is called with the parameters (true, 1500): The channel will turn on and in 1.5s it will turn off again.

A monoflop can be used as a failsafe mechanism. For example: Lets assume you have a RS485 bus and a IO-4 Bricklet 2.0 is connected to one of the slave stacks. You can now call this function every second, with a time parameter of two seconds. The channel will be high all the time. If now the RS485 connection is lost, the channel will turn low in at most two seconds.

int io4_v2_get_monoflop(IO4V2 *io4_v2, uint8_t channel, bool *ret_value, uint32_t *ret_time, uint32_t *ret_time_remaining)

Returns (for the given channel) the current value and the time as set by io4_v2_set_monoflop() as well as the remaining time until the value flips.

If the timer is not running currently, the remaining time will be returned as 0.

int io4_v2_get_edge_count(IO4V2 *io4_v2, uint8_t channel, bool reset_counter, uint32_t *ret_count)

Returns the current value of the edge counter for the selected channel. You can configure the edges that are counted with io4_v2_set_edge_count_configuration().

If you set the reset counter to true, the count is set back to 0 directly after it is read.

int io4_v2_set_edge_count_configuration(IO4V2 *io4_v2, uint8_t channel, uint8_t edge_type, uint8_t debounce)

Configures the edge counter for a specific channel.

The edge type parameter configures if rising edges, falling edges or both are counted if the channel is configured for input. Possible edge types are:

  • 0 = rising (default)
  • 1 = falling
  • 2 = both

The debounce time is given in ms.

Configuring an edge counter resets its value to 0.

If you don't know what any of this means, just leave it at default. The default configuration is very likely OK for you.

Default values: 0 (edge type) and 100ms (debounce time)

The following defines are available for this function:

  • IO4_V2_EDGE_TYPE_RISING = 0
  • IO4_V2_EDGE_TYPE_FALLING = 1
  • IO4_V2_EDGE_TYPE_BOTH = 2
int io4_v2_get_edge_count_configuration(IO4V2 *io4_v2, uint8_t channel, uint8_t *ret_edge_type, uint8_t *ret_debounce)

Returns the edge type and debounce time for the selected channel as set by io4_v2_set_edge_count_configuration().

The following defines are available for this function:

  • IO4_V2_EDGE_TYPE_RISING = 0
  • IO4_V2_EDGE_TYPE_FALLING = 1
  • IO4_V2_EDGE_TYPE_BOTH = 2
int io4_v2_set_pwm_configuration(IO4V2 *io4_v2, uint8_t channel, uint32_t frequency, uint16_t duty_cycle)

Activates a PWM for the given channel with the frequency given in 1/10Hz and the duty cycle given in 1/100%.

You need to set the channel to output before you call this function, otherwise it will be ignored. To turn the PWM off again, you can set the frequency to 0 or any other function that changes a value of the channel (e.g. io4_v2_set_selected_value()).

The maximum frequency value is 320000000 (32MHz). The maximum duty cycle value is 10000 (100%).

The default values are 0, 0.

int io4_v2_get_pwm_configuration(IO4V2 *io4_v2, uint8_t channel, uint32_t *ret_frequency, uint16_t *ret_duty_cycle)

Returns the PWM configuration as set by io4_v2_set_pwm_configuration().

int io4_v2_get_api_version(IO4V2 *io4_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 io4_v2_get_response_expected(IO4V2 *io4_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 io4_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 io4_v2_set_response_expected() for the list of function ID defines available for this function.

int io4_v2_set_response_expected(IO4V2 *io4_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:

  • IO4_V2_FUNCTION_SET_VALUE = 1
  • IO4_V2_FUNCTION_SET_SELECTED_VALUE = 3
  • IO4_V2_FUNCTION_SET_CONFIGURATION = 4
  • IO4_V2_FUNCTION_SET_INPUT_VALUE_CALLBACK_CONFIGURATION = 6
  • IO4_V2_FUNCTION_SET_ALL_INPUT_VALUE_CALLBACK_CONFIGURATION = 8
  • IO4_V2_FUNCTION_SET_MONOFLOP = 10
  • IO4_V2_FUNCTION_SET_EDGE_COUNT_CONFIGURATION = 13
  • IO4_V2_FUNCTION_SET_PWM_CONFIGURATION = 15
  • IO4_V2_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • IO4_V2_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • IO4_V2_FUNCTION_RESET = 243
  • IO4_V2_FUNCTION_WRITE_UID = 248
int io4_v2_set_response_expected_all(IO4V2 *io4_v2, bool response_expected)

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

int io4_v2_get_spitfp_error_count(IO4V2 *io4_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 io4_v2_set_bootloader_mode(IO4V2 *io4_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:

  • IO4_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • IO4_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • IO4_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • IO4_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • IO4_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • IO4_V2_BOOTLOADER_STATUS_OK = 0
  • IO4_V2_BOOTLOADER_STATUS_INVALID_MODE = 1
  • IO4_V2_BOOTLOADER_STATUS_NO_CHANGE = 2
  • IO4_V2_BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • IO4_V2_BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • IO4_V2_BOOTLOADER_STATUS_CRC_MISMATCH = 5
int io4_v2_get_bootloader_mode(IO4V2 *io4_v2, uint8_t *ret_mode)

Returns the current bootloader mode, see io4_v2_set_bootloader_mode().

The following defines are available for this function:

  • IO4_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • IO4_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • IO4_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • IO4_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • IO4_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
int io4_v2_set_write_firmware_pointer(IO4V2 *io4_v2, uint32_t pointer)

Sets the firmware pointer for io4_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 io4_v2_write_firmware(IO4V2 *io4_v2, uint8_t data[64], uint8_t *ret_status)

Writes 64 Bytes of firmware at the position as written by io4_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 io4_v2_set_status_led_config(IO4V2 *io4_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:

  • IO4_V2_STATUS_LED_CONFIG_OFF = 0
  • IO4_V2_STATUS_LED_CONFIG_ON = 1
  • IO4_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • IO4_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
int io4_v2_get_status_led_config(IO4V2 *io4_v2, uint8_t *ret_config)

Returns the configuration as set by io4_v2_set_status_led_config()

The following defines are available for this function:

  • IO4_V2_STATUS_LED_CONFIG_OFF = 0
  • IO4_V2_STATUS_LED_CONFIG_ON = 1
  • IO4_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • IO4_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
int io4_v2_get_chip_temperature(IO4V2 *io4_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 io4_v2_reset(IO4V2 *io4_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 io4_v2_write_uid(IO4V2 *io4_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 io4_v2_read_uid(IO4V2 *io4_v2, uint32_t *ret_uid)

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

int io4_v2_get_identity(IO4V2 *io4_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 io4_v2_register_callback(IO4V2 *io4_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 io4_v2_get_configuration(IO4V2 *io4_v2, uint8_t channel, char *ret_direction, bool *ret_value)

Returns the channel configuration as set by io4_v2_set_configuration().

The following defines are available for this function:

  • IO4_V2_DIRECTION_IN = 'i'
  • IO4_V2_DIRECTION_OUT = 'o'
int io4_v2_set_input_value_callback_configuration(IO4V2 *io4_v2, uint8_t channel, uint32_t period, bool value_has_to_change)

This callback can be configured per channel.

The period in ms is the period with which the IO4_V2_CALLBACK_INPUT_VALUE callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

The default value is (0, false).

int io4_v2_get_input_value_callback_configuration(IO4V2 *io4_v2, uint8_t channel, uint32_t *ret_period, bool *ret_value_has_to_change)

Returns the callback configuration for the given channel as set by io4_v2_set_input_value_callback_configuration().

int io4_v2_set_all_input_value_callback_configuration(IO4V2 *io4_v2, uint32_t period, bool value_has_to_change)

The period in ms is the period with which the IO4_V2_CALLBACK_ALL_INPUT_VALUE callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

The default value is (0, false).

int io4_v2_get_all_input_value_callback_configuration(IO4V2 *io4_v2, uint32_t *ret_period, bool *ret_value_has_to_change)

Returns the callback configuration as set by io4_v2_set_all_input_value_callback_configuration().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the io4_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);
}

io4_v2_register_callback(&io4_v2, IO4_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.

IO4_V2_CALLBACK_INPUT_VALUE
void callback(uint8_t channel, bool changed, bool value, void *user_data)

This callback is triggered periodically according to the configuration set by io4_v2_set_input_value_callback_configuration().

The parameters are the channel, a value-changed indicator and the actual value for the channel. The changed parameter is true if the value has changed since the last callback.

IO4_V2_CALLBACK_ALL_INPUT_VALUE
void callback(bool changed[4], bool value[4], void *user_data)

This callback is triggered periodically according to the configuration set by io4_v2_set_all_input_value_callback_configuration().

The parameters are the same as io4_v2_get_value(). Additional the changed parameter is true if the value has changed since the last callback.

IO4_V2_CALLBACK_MONOFLOP_DONE
void callback(uint8_t channel, bool value, void *user_data)

This callback is triggered whenever a monoflop timer reaches 0. The parameters contain the channel and the current value of the channel (the value after the monoflop).

Constants

IO4_V2_DEVICE_IDENTIFIER

This constant is used to identify a IO-4 Bricklet 2.0.

The io4_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.

IO4_V2_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a IO-4 Bricklet 2.0.