C/C++ - Piezo Speaker Bricklet 2.0

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

Alarm

Download (example_alarm.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_piezo_speaker_v2.h"

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

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

    // Create device object
    PiezoSpeakerV2 ps;
    piezo_speaker_v2_create(&ps, 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

    // 10 seconds of loud annoying fast alarm
    piezo_speaker_v2_set_alarm(&ps, 800, 2000, 10, 1, 10, 10000);

    printf("Press key to exit\n");
    getchar();
    piezo_speaker_v2_destroy(&ps);
    ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
    return 0;
}

Beep

Download (example_beep.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_piezo_speaker_v2.h"

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

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

    // Create device object
    PiezoSpeakerV2 ps;
    piezo_speaker_v2_create(&ps, 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

    // Make 2 second beep with a frequency of 1kHz
    piezo_speaker_v2_set_beep(&ps, 1000, 0, 2000);

    printf("Press key to exit\n");
    getchar();
    piezo_speaker_v2_destroy(&ps);
    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 output parameters. 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
  • E_INVALID_UID = -13
  • E_NON_ASCII_CHAR_IN_SECRET = -14

as defined in ip_connection.h.

All functions listed below are thread-safe.

Basic Functions

void piezo_speaker_v2_create(PiezoSpeakerV2 *piezo_speaker_v2, const char *uid, IPConnection *ipcon)

Creates the device object piezo_speaker_v2 with the unique device ID uid and adds it to the IPConnection ipcon:

PiezoSpeakerV2 piezo_speaker_v2;
piezo_speaker_v2_create(&piezo_speaker_v2, "YOUR_DEVICE_UID", &ipcon);

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

void piezo_speaker_v2_destroy(PiezoSpeakerV2 *piezo_speaker_v2)

Removes the device object piezo_speaker_v2 from its IPConnection and destroys it. The device object cannot be used anymore afterwards.

int piezo_speaker_v2_set_beep(PiezoSpeakerV2 *piezo_speaker_v2, uint16_t frequency, uint8_t volume, uint32_t duration)

Beeps with the given frequency and volume for the duration in ms.

For example: If you set a duration of 1000, with a volume of 10 and a frequency value of 2000 the piezo buzzer will beep with maximum loudness for one second with a frequency of 2 kHz.

A duration of 0 stops the current beep if any is ongoing. A duration of 4294967295 results in an infinite beep.

The ranges are:

  • Frequency: 50Hz - 15000Hz
  • Volume: 0 - 10
  • Duration: 0ms - 4294967295ms

The following constants are available for this function:

  • PIEZO_SPEAKER_V2_BEEP_DURATION_OFF = 0
  • PIEZO_SPEAKER_V2_BEEP_DURATION_INFINITE = 4294967295
int piezo_speaker_v2_get_beep(PiezoSpeakerV2 *piezo_speaker_v2, uint16_t *ret_frequency, uint8_t *ret_volume, uint32_t *ret_duration, uint32_t *ret_duration_remaining)

Returns the last beep settings as set by piezo_speaker_v2_set_beep(). If a beep is currently running it also returns the remaining duration of the beep in ms.

If the frequency or volume is updated during a beep (with piezo_speaker_v2_update_frequency() or piezo_speaker_v2_update_volume()) this function returns the updated value.

The following constants are available for this function:

  • PIEZO_SPEAKER_V2_BEEP_DURATION_OFF = 0
  • PIEZO_SPEAKER_V2_BEEP_DURATION_INFINITE = 4294967295
int piezo_speaker_v2_set_alarm(PiezoSpeakerV2 *piezo_speaker_v2, uint16_t start_frequency, uint16_t end_frequency, uint16_t step_size, uint16_t step_delay, uint8_t volume, uint32_t duration)

Creates an alarm (a tone that goes back and force between two specified frequencies).

The following parameters can be set:

  • Start Frequency: Start frequency of the alarm in Hz.
  • End Frequency: End frequency of the alarm in Hz.
  • Step Size: Size of one step of the sweep between the start/end frequencies in Hz.
  • Step Delay: Delay between two steps (duration of time that one tone is used in a sweep) in ms.
  • Duration: Duration of the alarm in ms.

A duration of 0 stops the current alarm if any is ongoing. A duration of 4294967295 results in an infinite alarm.

Below you can find two sets of example settings that you can try out. You can use these as a starting point to find an alarm signal that suits your application.

Example 1: 10 seconds of loud annoying fast alarm

  • Start Frequency = 800
  • End Frequency = 2000
  • Step Size = 10
  • Step Delay = 1
  • Volume = 10
  • Duration = 10000

Example 2: 10 seconds of soft siren sound with slow build-up

  • Start Frequency = 250
  • End Frequency = 750
  • Step Size = 1
  • Step Delay = 5
  • Volume = 0
  • Duration = 10000

The ranges are:

  • Start Frequency: 50Hz - 14999Hz (has to be smaller than end frequency)
  • End Frequency: 51Hz - 15000Hz (has to be bigger than start frequency)
  • Step Size: 1Hz - 65535Hz (has to be small enough to fit into the frequency range)
  • Step Delay: 1ms - 65535ms (has to be small enough to fit into the duration)
  • Volume: 0 - 10
  • Duration: 0ms - 4294967295ms

The following constants are available for this function:

  • PIEZO_SPEAKER_V2_ALARM_DURATION_OFF = 0
  • PIEZO_SPEAKER_V2_ALARM_DURATION_INFINITE = 4294967295
int piezo_speaker_v2_get_alarm(PiezoSpeakerV2 *piezo_speaker_v2, uint16_t *ret_start_frequency, uint16_t *ret_end_frequency, uint16_t *ret_step_size, uint16_t *ret_step_delay, uint8_t *ret_volume, uint32_t *ret_duration, uint32_t *ret_duration_remaining, uint16_t *ret_current_frequency)

Returns the last alarm settings as set by piezo_speaker_v2_set_alarm(). If an alarm is currently running it also returns the remaining duration of the alarm in ms as well as the current frequency of the alarm in Hz.

If the volume is updated during a beep (with piezo_speaker_v2_update_volume()) this function returns the updated value.

The following constants are available for this function:

  • PIEZO_SPEAKER_V2_ALARM_DURATION_OFF = 0
  • PIEZO_SPEAKER_V2_ALARM_DURATION_INFINITE = 4294967295
int piezo_speaker_v2_update_volume(PiezoSpeakerV2 *piezo_speaker_v2, uint8_t volume)

Updates the volume of an ongoing beep or alarm. The range of the volume is 0 to 10.

int piezo_speaker_v2_update_frequency(PiezoSpeakerV2 *piezo_speaker_v2, uint16_t frequency)

Updates the frequency of an ongoing beep. The range of the frequency is 50Hz to 15000Hz.

Advanced Functions

int piezo_speaker_v2_get_api_version(PiezoSpeakerV2 *piezo_speaker_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 piezo_speaker_v2_get_response_expected(PiezoSpeakerV2 *piezo_speaker_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 piezo_speaker_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.

The following constants are available for this function:

  • PIEZO_SPEAKER_V2_FUNCTION_SET_BEEP = 1
  • PIEZO_SPEAKER_V2_FUNCTION_SET_ALARM = 3
  • PIEZO_SPEAKER_V2_FUNCTION_UPDATE_VOLUME = 5
  • PIEZO_SPEAKER_V2_FUNCTION_UPDATE_FREQUENCY = 6
  • PIEZO_SPEAKER_V2_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • PIEZO_SPEAKER_V2_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • PIEZO_SPEAKER_V2_FUNCTION_RESET = 243
  • PIEZO_SPEAKER_V2_FUNCTION_WRITE_UID = 248
int piezo_speaker_v2_set_response_expected(PiezoSpeakerV2 *piezo_speaker_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 constants are available for this function:

  • PIEZO_SPEAKER_V2_FUNCTION_SET_BEEP = 1
  • PIEZO_SPEAKER_V2_FUNCTION_SET_ALARM = 3
  • PIEZO_SPEAKER_V2_FUNCTION_UPDATE_VOLUME = 5
  • PIEZO_SPEAKER_V2_FUNCTION_UPDATE_FREQUENCY = 6
  • PIEZO_SPEAKER_V2_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • PIEZO_SPEAKER_V2_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • PIEZO_SPEAKER_V2_FUNCTION_RESET = 243
  • PIEZO_SPEAKER_V2_FUNCTION_WRITE_UID = 248
int piezo_speaker_v2_set_response_expected_all(PiezoSpeakerV2 *piezo_speaker_v2, bool response_expected)

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

int piezo_speaker_v2_get_spitfp_error_count(PiezoSpeakerV2 *piezo_speaker_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 piezo_speaker_v2_set_bootloader_mode(PiezoSpeakerV2 *piezo_speaker_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 constants are available for this function:

  • PIEZO_SPEAKER_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • PIEZO_SPEAKER_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • PIEZO_SPEAKER_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • PIEZO_SPEAKER_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • PIEZO_SPEAKER_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • PIEZO_SPEAKER_V2_BOOTLOADER_STATUS_OK = 0
  • PIEZO_SPEAKER_V2_BOOTLOADER_STATUS_INVALID_MODE = 1
  • PIEZO_SPEAKER_V2_BOOTLOADER_STATUS_NO_CHANGE = 2
  • PIEZO_SPEAKER_V2_BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • PIEZO_SPEAKER_V2_BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • PIEZO_SPEAKER_V2_BOOTLOADER_STATUS_CRC_MISMATCH = 5
int piezo_speaker_v2_get_bootloader_mode(PiezoSpeakerV2 *piezo_speaker_v2, uint8_t *ret_mode)

Returns the current bootloader mode, see piezo_speaker_v2_set_bootloader_mode().

The following constants are available for this function:

  • PIEZO_SPEAKER_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • PIEZO_SPEAKER_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • PIEZO_SPEAKER_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • PIEZO_SPEAKER_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • PIEZO_SPEAKER_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
int piezo_speaker_v2_set_write_firmware_pointer(PiezoSpeakerV2 *piezo_speaker_v2, uint32_t pointer)

Sets the firmware pointer for piezo_speaker_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 piezo_speaker_v2_write_firmware(PiezoSpeakerV2 *piezo_speaker_v2, uint8_t data[64], uint8_t *ret_status)

Writes 64 Bytes of firmware at the position as written by piezo_speaker_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 piezo_speaker_v2_set_status_led_config(PiezoSpeakerV2 *piezo_speaker_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 constants are available for this function:

  • PIEZO_SPEAKER_V2_STATUS_LED_CONFIG_OFF = 0
  • PIEZO_SPEAKER_V2_STATUS_LED_CONFIG_ON = 1
  • PIEZO_SPEAKER_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • PIEZO_SPEAKER_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
int piezo_speaker_v2_get_status_led_config(PiezoSpeakerV2 *piezo_speaker_v2, uint8_t *ret_config)

Returns the configuration as set by piezo_speaker_v2_set_status_led_config()

The following constants are available for this function:

  • PIEZO_SPEAKER_V2_STATUS_LED_CONFIG_OFF = 0
  • PIEZO_SPEAKER_V2_STATUS_LED_CONFIG_ON = 1
  • PIEZO_SPEAKER_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • PIEZO_SPEAKER_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
int piezo_speaker_v2_get_chip_temperature(PiezoSpeakerV2 *piezo_speaker_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 piezo_speaker_v2_reset(PiezoSpeakerV2 *piezo_speaker_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 piezo_speaker_v2_write_uid(PiezoSpeakerV2 *piezo_speaker_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 piezo_speaker_v2_read_uid(PiezoSpeakerV2 *piezo_speaker_v2, uint32_t *ret_uid)

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

int piezo_speaker_v2_get_identity(PiezoSpeakerV2 *piezo_speaker_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 piezo_speaker_v2_register_callback(PiezoSpeakerV2 *piezo_speaker_v2, int16_t callback_id, void (*function)(void), 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.

Callbacks

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

piezo_speaker_v2_register_callback(&piezo_speaker_v2, PIEZO_SPEAKER_V2_CALLBACK_EXAMPLE, (void (*)(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.

PIEZO_SPEAKER_V2_CALLBACK_BEEP_FINISHED
void callback(void *user_data)

This callback is triggered if a beep set by piezo_speaker_v2_set_beep() is finished

PIEZO_SPEAKER_V2_CALLBACK_ALARM_FINISHED
void callback(void *user_data)

This callback is triggered if a alarm set by piezo_speaker_v2_set_alarm() is finished

Constants

PIEZO_SPEAKER_V2_DEVICE_IDENTIFIER

This constant is used to identify a Piezo Speaker Bricklet 2.0.

The piezo_speaker_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.

PIEZO_SPEAKER_V2_DEVICE_DISPLAY_NAME

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