MQTT - IO-16 Bricklet 2.0

This is the description of the MQTT API bindings for the IO-16 Bricklet 2.0. General information and technical specifications for the IO-16 Bricklet 2.0 are summarized in its hardware description.

An installation guide for the MQTT API bindings is part of their general description.

Examples

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

Interrupt

Download (example-interrupt.txt)

1
2
3
4
5
6
7
8
9
# Change XYZ to the UID of your IO-16 Bricklet 2.0

setup:
    # Handle incoming input value callbacks
    subscribe to tinkerforge/callback/io16_v2_bricklet/XYZ/input_value
    publish '{"register": true}' to tinkerforge/register/io16_v2_bricklet/XYZ/input_value # Register input_value callback
    
    # Set period for input value (channel 4) callback to 0.5s (500ms)
    publish '{"channel": 4, "period": 500, "value_has_to_change": false}' to tinkerforge/request/io16_v2_bricklet/XYZ/set_input_value_callback_configuration

Output

Download (example-output.txt)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
# Change XYZ to the UID of your IO-16 Bricklet 2.0

setup:
    # Configure channel 7 as output low
    publish '{"channel": 7, "direction": "out", "value": false}' to tinkerforge/request/io16_v2_bricklet/XYZ/set_configuration 
    
    # Set channel 7 alternating high/low 10 times with 100 ms delay
    for i in 0 1 2 3 4 5 6 7 8 9; do
    
        wait for 0.1s 
    
        publish '{"channel": 7, "value": true}' to tinkerforge/request/io16_v2_bricklet/XYZ/set_selected_value 
    
        wait for 0.1s 
    
        publish '{"channel": 7, "value": false}' to tinkerforge/request/io16_v2_bricklet/XYZ/set_selected_value 
    
    done

API

All published payloads to and from the MQTT bindings are in JSON format.

If an error occures, the bindings publish a JSON object containing the error message as attribute "_ERROR". It is published on the corresponding response topic: .../response/... for .../request/... and .../callback/... for .../register/....

The Bricklet has sixteen channels that are named 0 to 15 in the API. The corresponding connectors on the Bricklet are labeled A0 to A7 for channel 0 to 7 and B0 to B7 for channels 8 to 15.

Basic Functions

request/io16_v2_bricklet/<UID>/set_value
Request payload:
 
  • value -- [bool,... (x16)]

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

Use request/io16_v2_bricklet/<UID>/set_selected_value to change only one output channel state.

For example: (True, True, False, False, ..., False) will turn the channels 0-1 high and the channels 2-15 low.

All running monoflop timers 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/io16_v2_bricklet/<UID>/set_configuration.

request/io16_v2_bricklet/<UID>/get_value
Response payload:
 
  • value -- [bool,... (x16)]

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/io16_v2_bricklet/<UID>/set_selected_value
Request payload:
 
  • channel -- int
  • value -- bool

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

A running monoflop timer 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/io16_v2_bricklet/<UID>/set_configuration.

request/io16_v2_bricklet/<UID>/set_configuration
Request payload:
 
  • channel -- int
  • direction -- string (has symbols)
  • value -- bool

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

The default configuration is input with pull-up.

The following symbols are available for this function:

for direction:

  • "In" = 'i'
  • "Out" = 'o'
request/io16_v2_bricklet/<UID>/get_configuration
Request payload:
 
  • channel -- int
Response payload:
 
  • direction -- string (has symbols)
  • value -- bool

Returns the channel configuration as set by request/io16_v2_bricklet/<UID>/set_configuration.

The following symbols are available for this function:

for direction:

  • "In" = 'i'
  • "Out" = 'o'

Advanced Functions

request/io16_v2_bricklet/<UID>/set_monoflop
Request payload:
 
  • channel -- int
  • value -- bool
  • time -- int

Configures a monoflop of the specified channel.

The second parameter is the desired value of the specified channel. A true means relay closed and a false means relay open.

The third parameter indicates the time (in ms) that the channels should hold the value.

If this function is called with the parameters (0, 1, 1500) channel 0 will close and in 1.5s channel 0 will open again

A monoflop can be used as a fail-safe mechanism. For example: Lets assume you have a RS485 bus and a IO-16 Bricklet 2.0 connected to one of the slave stacks. You can now call this function every second, with a time parameter of two seconds and channel 0 closed. Channel 0 will be closed all the time. If now the RS485 connection is lost, then channel 0 will be opened in at most two seconds.

request/io16_v2_bricklet/<UID>/get_monoflop
Request payload:
 
  • channel -- int
Response payload:
 
  • value -- bool
  • time -- int
  • time_remaining -- int

Returns (for the given channel) the current value and the time as set by request/io16_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/io16_v2_bricklet/<UID>/get_edge_count
Request payload:
 
  • channel -- int
  • reset_counter -- bool
Response payload:
 
  • count -- int

Returns the current value of the edge counter for the selected channel. You can configure the edges that are counted with request/io16_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.

request/io16_v2_bricklet/<UID>/set_edge_count_configuration
Request payload:
 
  • channel -- int
  • edge_type -- int (has symbols)
  • debounce -- int

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 symbols are available for this function:

for edge_type:

  • "Rising" = 0
  • "Falling" = 1
  • "Both" = 2
request/io16_v2_bricklet/<UID>/get_edge_count_configuration
Request payload:
 
  • channel -- int
Response payload:
 
  • edge_type -- int (has symbols)
  • debounce -- int

Returns the edge type and debounce time for the selected channel as set by request/io16_v2_bricklet/<UID>/set_edge_count_configuration.

The following symbols are available for this function:

for edge_type:

  • "Rising" = 0
  • "Falling" = 1
  • "Both" = 2
request/io16_v2_bricklet/<UID>/get_spitfp_error_count
Response payload:
 
  • error_count_ack_checksum -- int
  • error_count_message_checksum -- int
  • error_count_frame -- int
  • error_count_overflow -- int

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/io16_v2_bricklet/<UID>/set_bootloader_mode
Request payload:
 
  • mode -- int (has symbols)
Response payload:
 
  • status -- int (has 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
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4

for status:

  • "OK" = 0
  • "InvalidMode" = 1
  • "NoChange" = 2
  • "EntryFunctionNotPresent" = 3
  • "DeviceIdentifierIncorrect" = 4
  • "CRCMismatch" = 5
request/io16_v2_bricklet/<UID>/get_bootloader_mode
Response payload:
 
  • mode -- int (has symbols)

Returns the current bootloader mode, see request/io16_v2_bricklet/<UID>/set_bootloader_mode.

The following symbols are available for this function:

for mode:

  • "Bootloader" = 0
  • "Firmware" = 1
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4
request/io16_v2_bricklet/<UID>/set_write_firmware_pointer
Request payload:
 
  • pointer -- int

Sets the firmware pointer for request/io16_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/io16_v2_bricklet/<UID>/write_firmware
Request payload:
 
  • data -- [int,... (x64)]
Response payload:
 
  • status -- int

Writes 64 Bytes of firmware at the position as written by request/io16_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/io16_v2_bricklet/<UID>/set_status_led_config
Request payload:
 
  • config -- int (has symbols)

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
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/io16_v2_bricklet/<UID>/get_status_led_config
Response payload:
 
  • config -- int (has symbols)

Returns the configuration as set by request/io16_v2_bricklet/<UID>/set_status_led_config

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/io16_v2_bricklet/<UID>/get_chip_temperature
Response payload:
 
  • temperature -- int

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.

request/io16_v2_bricklet/<UID>/reset

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/io16_v2_bricklet/<UID>/write_uid
Request payload:
 
  • uid -- int

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/io16_v2_bricklet/<UID>/read_uid
Response payload:
 
  • uid -- int

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

request/io16_v2_bricklet/<UID>/get_identity
Response payload:
 
  • uid -- string
  • connected_uid -- string
  • position -- string
  • hardware_version -- [int,int,int]
  • firmware_version -- [int,int,int]
  • device_identifier -- int (has symbols)
  • _display_name -- 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' or 'd'.

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-16 2.0's name in a human readable form.

Callback Configuration Functions

request/io16_v2_bricklet/<UID>/set_input_value_callback_configuration
Request payload:
 
  • channel -- int
  • period -- int
  • value_has_to_change -- bool

This callback can be configured per channel.

The period in ms is the period with which the register/io16_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.

The default value is (0, false).

request/io16_v2_bricklet/<UID>/get_input_value_callback_configuration
Request payload:
 
  • channel -- int
Response payload:
 
  • period -- int
  • value_has_to_change -- bool

Returns the callback configuration as set by request/io16_v2_bricklet/<UID>/set_input_value_callback_configuration.

request/io16_v2_bricklet/<UID>/set_all_input_value_callback_configuration
Request payload:
 
  • period -- int
  • value_has_to_change -- bool

The period in ms is the period with which the register/io16_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.

The default value is (0, false).

request/io16_v2_bricklet/<UID>/get_all_input_value_callback_configuration
Response payload:
 
  • period -- int
  • value_has_to_change -- bool

Returns the callback configuration as set by request/io16_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.

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.

register/io16_v2_bricklet/<UID>/input_value
Request payload:
 
  • register -- bool
Response payload:
 
  • channel -- int
  • changed -- bool
  • value -- bool

A callback can be registered for this event by publishing to the .../register/io16_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/io16_v2_bricklet/<UID>/input_value[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically according to the configuration set by request/io16_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/io16_v2_bricklet/<UID>/all_input_value
Request payload:
 
  • register -- bool
Response payload:
 
  • changed -- [bool,... (x16)]
  • value -- [bool,... (x16)]

A callback can be registered for this event by publishing to the .../register/io16_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/io16_v2_bricklet/<UID>/all_input_value[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically according to the configuration set by request/io16_v2_bricklet/<UID>/set_all_input_value_callback_configuration.

The callback payload members are the same as request/io16_v2_bricklet/<UID>/get_value. Additional the changed parameter is true if the value has changed since the last callback.

register/io16_v2_bricklet/<UID>/monoflop_done
Request payload:
 
  • register -- bool
Response payload:
 
  • channel -- int
  • value -- bool

A callback can be registered for this event by publishing to the .../register/io16_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/io16_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).