MQTT - IO-4 Bricklet 2.0¶

Input¶

Download (example-input.txt)

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# Change XYZ to the UID of your IO-4 Bricklet 2.0

setup:
    # Get current value
    subscribe to tinkerforge/response/io4_v2_bricklet/XYZ/get_value
    publish '' to tinkerforge/request/io4_v2_bricklet/XYZ/get_value

Interrupt¶

Download (example-interrupt.txt)

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# Change XYZ to the UID of your IO-4 Bricklet 2.0

setup:
    # Handle incoming input value callbacks
    subscribe to tinkerforge/callback/io4_v2_bricklet/XYZ/input_value
    publish '{"register": true}' to tinkerforge/register/io4_v2_bricklet/XYZ/input_value # Register input_value callback

    # Set period for input value (channel 1) callback to 0.5s (500ms)
    publish '{"channel": 1, "period": 500, "value_has_to_change": false}' to tinkerforge/request/io4_v2_bricklet/XYZ/set_input_value_callback_configuration

Output¶

Download (example-output.txt)

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# Change XYZ to the UID of your IO-4 Bricklet 2.0

setup:
    # Configure channel 3 as output low
    publish '{"channel": 3, "direction": "out", "value": false}' to tinkerforge/request/io4_v2_bricklet/XYZ/set_configuration

    # Set channel 3 alternating high/low 10 times with 100 ms delay
    for i in 0..9

        wait for 0.1s

        publish '{"channel": 3, "value": true}' to tinkerforge/request/io4_v2_bricklet/XYZ/set_selected_value

        wait for 0.1s

        publish '{"channel": 3, "value": false}' to tinkerforge/request/io4_v2_bricklet/XYZ/set_selected_value

    endfor

Basic Functions¶

request/io4_v2_bricklet/<UID>/set_value¶

Request:	value – Type: [bool, ...], Length: 4
Response:	no response

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 request/io4_v2_bricklet/<UID>/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.

All running monoflop timers and PWMs will be aborted if this function is called.

Note

This function does nothing for channels that are configured as input. Pull-up resistors can be switched on with request/io4_v2_bricklet/<UID>/set_configuration.

request/io4_v2_bricklet/<UID>/get_value¶

Request:	empty payload
Response:	value – Type: [bool, ...], Length: 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.

request/io4_v2_bricklet/<UID>/set_selected_value¶

Request:	channel – Type: int, Range: [0 to 3] value – Type: bool
Response:	no response

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

A running monoflop timer or PWM for the specific channel will be aborted if this function is called.

Note

This function does nothing for channels that are configured as input. Pull-up resistors can be switched on with request/io4_v2_bricklet/<UID>/set_configuration.

request/io4_v2_bricklet/<UID>/set_configuration¶

Request:	channel – Type: int, Range: [0 to 3] direction – Type: char, Range: See symbols, Default: "i" value – Type: bool, Default: true
Response:	no response

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.

A running monoflop timer or PWM for the specific channel will be aborted if this function is called.

The following symbols are available for this function:

For direction:

• "in" = "i"
• "out" = "o"

request/io4_v2_bricklet/<UID>/get_configuration¶

Request:	channel – Type: int, Range: [0 to 3]
Response:	direction – Type: char, Range: See symbols, Default: "i" value – Type: bool, Default: true

Returns the channel configuration as set by request/io4_v2_bricklet/<UID>/set_configuration.

The following symbols are available for this function:

For direction:

• "in" = "i"
• "out" = "o"

Advanced Functions¶

request/io4_v2_bricklet/<UID>/set_monoflop¶

Request:	channel – Type: int, Range: [0 to 3] value – Type: bool time – Type: int, Unit: 1 ms, Range: [0 to 232 - 1]
Response:	no response

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 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 PWM for the selected channel will be aborted if this function is called.

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.

request/io4_v2_bricklet/<UID>/get_monoflop¶

Request:	channel – Type: int, Range: [0 to 3]
Response:	value – Type: bool time – Type: int, Unit: 1 ms, Range: [0 to 232 - 1] time_remaining – Type: int, Unit: 1 ms, Range: [0 to 232 - 1]

Returns (for the given channel) the current value and the time as set by request/io4_v2_bricklet/<UID>/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.

request/io4_v2_bricklet/<UID>/get_edge_count¶

Request:	channel – Type: int, Range: [0 to 3] reset_counter – Type: bool
Response:	count – Type: int, Range: [0 to 232 - 1]

Returns the current value of the edge counter for the selected channel. You can configure the edges that are counted with request/io4_v2_bricklet/<UID>/set_edge_count_configuration.

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

Note

Calling this function is only allowed for channels configured as input.

request/io4_v2_bricklet/<UID>/set_edge_count_configuration¶

Request:	channel – Type: int, Range: [0 to 3] edge_type – Type: int, Range: See symbols, Default: 0 debounce – Type: int, Unit: 1 ms, Range: [0 to 255], Default: 100
Response:	no response

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
• 1 = falling
• 2 = both

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.

Note

Calling this function is only allowed for channels configured as input.

The following symbols are available for this function:

For edge_type:

• "rising" = 0
• "falling" = 1
• "both" = 2

request/io4_v2_bricklet/<UID>/get_edge_count_configuration¶

Request:	channel – Type: int, Range: [0 to 3]
Response:	edge_type – Type: int, Range: See symbols, Default: 0 debounce – Type: int, Unit: 1 ms, Range: [0 to 255], Default: 100

Returns the edge type and debounce time for the selected channel as set by request/io4_v2_bricklet/<UID>/set_edge_count_configuration.

Note

Calling this function is only allowed for channels configured as input.

The following symbols are available for this function:

For edge_type:

• "rising" = 0
• "falling" = 1
• "both" = 2

request/io4_v2_bricklet/<UID>/set_pwm_configuration¶

Request:	channel – Type: int, Range: [0 to 3] frequency – Type: int, Unit: 1/10 Hz, Range: [0 to 320000000], Default: 0 duty_cycle – Type: int, Unit: 1/100 %, Range: [0 to 10000], Default: 0
Response:	no response

Activates a PWM for the given channel.

You need to set the channel to output before you call this function, otherwise it will report an invalid parameter error. 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. request/io4_v2_bricklet/<UID>/set_selected_value).

A running monoflop timer for the given channel will be aborted if this function is called.

request/io4_v2_bricklet/<UID>/get_pwm_configuration¶

Request:	channel – Type: int, Range: [0 to 3]
Response:	frequency – Type: int, Unit: 1/10 Hz, Range: [0 to 320000000], Default: 0 duty_cycle – Type: int, Unit: 1/100 %, Range: [0 to 10000], Default: 0

Returns the PWM configuration as set by request/io4_v2_bricklet/<UID>/set_pwm_configuration.

request/io4_v2_bricklet/<UID>/get_spitfp_error_count¶

Request:	empty payload
Response:	error_count_ack_checksum – Type: int, Range: [0 to 232 - 1] error_count_message_checksum – Type: int, Range: [0 to 232 - 1] error_count_frame – Type: int, Range: [0 to 232 - 1] error_count_overflow – Type: int, Range: [0 to 232 - 1]

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.

request/io4_v2_bricklet/<UID>/set_status_led_config¶

Request:	config – Type: int, Range: See symbols, Default: 3
Response:	no response

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 symbols are available for this function:

For config:

• "off" = 0
• "on" = 1
• "show_heartbeat" = 2
• "show_status" = 3

request/io4_v2_bricklet/<UID>/get_status_led_config¶

Request:	empty payload
Response:	config – Type: int, Range: See symbols, Default: 3

Returns the configuration as set by request/io4_v2_bricklet/<UID>/set_status_led_config

The following symbols are available for this function:

For config:

• "off" = 0
• "on" = 1
• "show_heartbeat" = 2
• "show_status" = 3

request/io4_v2_bricklet/<UID>/get_chip_temperature¶

Request:	empty payload
Response:	temperature – Type: int, Unit: 1 °C, Range: [-215 to 215 - 1]

Returns the temperature 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.

request/io4_v2_bricklet/<UID>/reset¶

Request:	empty payload
Response:	no response

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!

request/io4_v2_bricklet/<UID>/get_identity¶

Request:

empty payload

Response:

uid – Type: string, Length: up to 8 connected_uid – Type: string, Length: up to 8 position – Type: char, Range: ["a" to "h", "z"] hardware_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255] firmware_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255] device_identifier – Type: int, Range: [0 to 216 - 1] _display_name – Type: string

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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

The device identifier numbers can be found here. If symbolic output is not disabled, the device identifier is mapped to the corresponding name in the format used in topics.

The display name contains the IO-4 2.0's name in a human readable form.

Callback Configuration Functions¶

request/io4_v2_bricklet/<UID>/set_input_value_callback_configuration¶

Request:	channel – Type: int, Range: [0 to 3] period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0 value_has_to_change – Type: bool, Default: false
Response:	no response

This callback can be configured per channel.

The period is the period with which the register/io4_v2_bricklet/<UID>/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.

request/io4_v2_bricklet/<UID>/get_input_value_callback_configuration¶

Request:	channel – Type: int, Range: [0 to 3]
Response:	period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0 value_has_to_change – Type: bool, Default: false

Returns the callback configuration for the given channel as set by request/io4_v2_bricklet/<UID>/set_input_value_callback_configuration.

request/io4_v2_bricklet/<UID>/set_all_input_value_callback_configuration¶

Request:	period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0 value_has_to_change – Type: bool, Default: false
Response:	no response

The period is the period with which the register/io4_v2_bricklet/<UID>/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.

request/io4_v2_bricklet/<UID>/get_all_input_value_callback_configuration¶

Request:	empty payload
Response:	period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0 value_has_to_change – Type: bool, Default: false

Returns the callback configuration as set by request/io4_v2_bricklet/<UID>/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 corresponding .../register/... topic and an optional suffix. This suffix can be used to deregister the callback later.

register/io4_v2_bricklet/<UID>/input_value¶

Register Request:	register – Type: bool
Callback Response:	channel – Type: int, Range: [0 to 3] changed – Type: bool value – Type: bool

A callback can be registered for this event by publishing to the .../register/io4_v2_bricklet/<UID>/input_value[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/io4_v2_bricklet/<UID>/input_value[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically according to the configuration set by request/io4_v2_bricklet/<UID>/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.

register/io4_v2_bricklet/<UID>/all_input_value¶

Register Request:	register – Type: bool
Callback Response:	changed – Type: [bool, ...], Length: 4 value – Type: [bool, ...], Length: 4

A callback can be registered for this event by publishing to the .../register/io4_v2_bricklet/<UID>/all_input_value[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/io4_v2_bricklet/<UID>/all_input_value[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically according to the configuration set by request/io4_v2_bricklet/<UID>/set_all_input_value_callback_configuration.

The callback payload members are the same as request/io4_v2_bricklet/<UID>/get_value. Additional the changed parameter is true if the value has changed since the last callback.

register/io4_v2_bricklet/<UID>/monoflop_done¶

Register Request:	register – Type: bool
Callback Response:	channel – Type: int, Range: [0 to 3] value – Type: bool

A callback can be registered for this event by publishing to the .../register/io4_v2_bricklet/<UID>/monoflop_done[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/io4_v2_bricklet/<UID>/monoflop_done[/<SUFFIX>] topic for each registered suffix.

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

Internal Functions¶

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

request/io4_v2_bricklet/<UID>/set_bootloader_mode¶

Request:	mode – Type: int, Range: See symbols
Response:	status – Type: int, Range: See symbols

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 symbols are available for this function:

For mode:

• "bootloader" = 0
• "firmware" = 1
• "bootloader_wait_for_reboot" = 2
• "firmware_wait_for_reboot" = 3
• "firmware_wait_for_erase_and_reboot" = 4

For status:

• "ok" = 0
• "invalid_mode" = 1
• "no_change" = 2
• "entry_function_not_present" = 3
• "device_identifier_incorrect" = 4
• "crc_mismatch" = 5

request/io4_v2_bricklet/<UID>/get_bootloader_mode¶

Request:	empty payload
Response:	mode – Type: int, Range: See symbols

Returns the current bootloader mode, see request/io4_v2_bricklet/<UID>/set_bootloader_mode.

The following symbols are available for this function:

For mode:

• "bootloader" = 0
• "firmware" = 1
• "bootloader_wait_for_reboot" = 2
• "firmware_wait_for_reboot" = 3
• "firmware_wait_for_erase_and_reboot" = 4

request/io4_v2_bricklet/<UID>/set_write_firmware_pointer¶

Request:	pointer – Type: int, Unit: 1 B, Range: [0 to 232 - 1]
Response:	no response

Sets the firmware pointer for request/io4_v2_bricklet/<UID>/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.

request/io4_v2_bricklet/<UID>/write_firmware¶

Request:	data – Type: [int, ...], Length: 64, Range: [0 to 255]
Response:	status – Type: int, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by request/io4_v2_bricklet/<UID>/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.

request/io4_v2_bricklet/<UID>/write_uid¶

Request:	uid – Type: int, Range: [0 to 232 - 1]
Response:	no response

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.

request/io4_v2_bricklet/<UID>/read_uid¶

Request:	empty payload
Response:	uid – Type: int, Range: [0 to 232 - 1]

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