Modbus - Multi Touch Bricklet 2.0

This is the description of the Modbus protocol for the Multi Touch Bricklet 2.0. General information and technical specifications for the Multi Touch Bricklet 2.0 are summarized in its hardware description.

API

A general description of the Modbus protocol structure can be found here.

Basic Functions

BrickletMultiTouchV2.get_touch_state
Function ID:
  • 1
Request:
  • empty payload
Response:
  • state – Type: bool[13]

Returns the current touch state. The state is given as a array of bools.

Element 0 to 11 represent the 12 electrodes and element 12 represents the proximity.

If an electrode is touched, the corresponding element is true. If a hand or similar is in proximity to the electrodes, element 12 is true.

The proximity is activated with a distance of 1-2cm. An electrode is already counted as touched if a finger is nearly touching the electrode. This means that you can put a piece of paper or foil or similar on top of a electrode to build a touch panel with a professional look.

If you want to get the value periodically, it is recommended to use the CALLBACK_TOUCH_STATE callback. You can set the callback configuration with set_touch_state_callback_configuration.

BrickletMultiTouchV2.recalibrate
Function ID:
  • 5
Request:
  • empty payload
Response:
  • no response

Recalibrates the electrodes. Call this function whenever you changed or moved you electrodes.

BrickletMultiTouchV2.set_electrode_config
Function ID:
  • 6
Request:
  • enabled_electrodes – Type: bool[13]
Response:
  • no response

Enables/disables electrodes with a bool array (see get_touch_state).

True enables the electrode, false disables the electrode. A disabled electrode will always return false as its state. If you don't need all electrodes you can disable the electrodes that are not needed.

It is recommended that you disable the proximity electrode (element 12) if the proximity feature is not needed. This will reduce the amount of traffic that is produced by the CALLBACK_TOUCH_STATE callback.

Disabling electrodes will also reduce power consumption.

Default: All electrodes enabled.

BrickletMultiTouchV2.get_electrode_config
Function ID:
  • 7
Request:
  • empty payload
Response:
  • enabled_electrodes – Type: bool[13]

Returns the electrode configuration, as set by set_electrode_config.

BrickletMultiTouchV2.set_electrode_sensitivity
Function ID:
  • 8
Request:
  • sensitivity – Type: uint8, Range: [0 to 255]
Response:
  • no response

Sets the sensitivity of the electrodes. An electrode with a high sensitivity will register a touch earlier then an electrode with a low sensitivity.

If you build a big electrode you might need to decrease the sensitivity, since the area that can be charged will get bigger. If you want to be able to activate an electrode from further away you need to increase the sensitivity.

After a new sensitivity is set, you likely want to call recalibrate to calibrate the electrodes with the newly defined sensitivity.

The valid sensitivity value range is 5-201.

The default sensitivity value is 181.

BrickletMultiTouchV2.get_electrode_sensitivity
Function ID:
  • 9
Request:
  • empty payload
Response:
  • sensitivity – Type: uint8, Range: [0 to 255]

Returns the current sensitivity, as set by set_electrode_sensitivity.

BrickletMultiTouchV2.set_touch_led_config
Function ID:
  • 10
Request:
  • config – Type: uint8, Range: See meanings
Response:
  • no response

Configures the touch LED to be either turned off, turned on, blink in heartbeat mode or show the touch state (electrode touched = LED on).

The default value is 3 (show touch state).

The following meanings are defined for the elements of this function:

For config:

  • 0 = Off
  • 1 = On
  • 2 = Show Heartbeat
  • 3 = Show Touch
BrickletMultiTouchV2.get_touch_led_config
Function ID:
  • 11
Request:
  • empty payload
Response:
  • config – Type: uint8, Range: See meanings

Returns the LED configuration as set by set_touch_led_config

The following meanings are defined for the elements of this function:

For config:

  • 0 = Off
  • 1 = On
  • 2 = Show Heartbeat
  • 3 = Show Touch

Advanced Functions

BrickletMultiTouchV2.get_spitfp_error_count
Function ID:
  • 234
Request:
  • empty payload
Response:
  • error_count_ack_checksum – Type: uint32, Range: [0 to 232 - 1]
  • error_count_message_checksum – Type: uint32, Range: [0 to 232 - 1]
  • error_count_frame – Type: uint32, Range: [0 to 232 - 1]
  • error_count_overflow – Type: uint32, 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.

BrickletMultiTouchV2.set_bootloader_mode
Function ID:
  • 235
Request:
  • mode – Type: uint8, Range: See meanings
Response:
  • status – Type: uint8, Range: See meanings

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 meanings are defined for the elements of this function:

For mode:

  • 0 = Bootloader
  • 1 = Firmware
  • 2 = Bootloader Wait For Reboot
  • 3 = Firmware Wait For Reboot
  • 4 = Firmware Wait For Erase And Reboot

For status:

  • 0 = OK
  • 1 = Invalid Mode
  • 2 = No Change
  • 3 = Entry Function Not Present
  • 4 = Device Identifier Incorrect
  • 5 = CRC Mismatch
BrickletMultiTouchV2.get_bootloader_mode
Function ID:
  • 236
Request:
  • empty payload
Response:
  • mode – Type: uint8, Range: See meanings

Returns the current bootloader mode, see set_bootloader_mode.

The following meanings are defined for the elements of this function:

For mode:

  • 0 = Bootloader
  • 1 = Firmware
  • 2 = Bootloader Wait For Reboot
  • 3 = Firmware Wait For Reboot
  • 4 = Firmware Wait For Erase And Reboot
BrickletMultiTouchV2.set_write_firmware_pointer
Function ID:
  • 237
Request:
  • pointer – Type: uint32, Range: [0 to 232 - 1]
Response:
  • no response

Sets the firmware pointer for 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.

BrickletMultiTouchV2.write_firmware
Function ID:
  • 238
Request:
  • data – Type: uint8[64], Range: [0 to 255]
Response:
  • status – Type: uint8, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by 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.

BrickletMultiTouchV2.set_status_led_config
Function ID:
  • 239
Request:
  • config – Type: uint8, Range: See meanings
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 meanings are defined for the elements of this function:

For config:

  • 0 = Off
  • 1 = On
  • 2 = Show Heartbeat
  • 3 = Show Status
BrickletMultiTouchV2.get_status_led_config
Function ID:
  • 240
Request:
  • empty payload
Response:
  • config – Type: uint8, Range: See meanings

Returns the configuration as set by set_status_led_config

The following meanings are defined for the elements of this function:

For config:

  • 0 = Off
  • 1 = On
  • 2 = Show Heartbeat
  • 3 = Show Status
BrickletMultiTouchV2.get_chip_temperature
Function ID:
  • 242
Request:
  • empty payload
Response:
  • temperature – Type: int16, Range: [-215 to 215 - 1]

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.

BrickletMultiTouchV2.reset
Function ID:
  • 243
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!

BrickletMultiTouchV2.write_uid
Function ID:
  • 248
Request:
  • uid – Type: uint32, 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.

BrickletMultiTouchV2.read_uid
Function ID:
  • 249
Request:
  • empty payload
Response:
  • uid – Type: uint32, Range: [0 to 232 - 1]

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

BrickletMultiTouchV2.get_identity
Function ID:
  • 255
Request:
  • empty payload
Response:
  • uid – Type: char[8]
  • connected_uid – Type: char[8]
  • position – Type: char
  • hardware_version – Type: uint8[3], Range: [0 to 255]
  • firmware_version – Type: uint8[3], Range: [0 to 255]
  • device_identifier – Type: uint16, Range: [0 to 216 - 1]

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

Callback Configuration Functions

BrickletMultiTouchV2.set_touch_state_callback_configuration
Function ID:
  • 2
Request:
  • period – Type: uint32, 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 CALLBACK_TOUCH_STATE 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.

BrickletMultiTouchV2.get_touch_state_callback_configuration
Function ID:
  • 3
Request:
  • empty payload
Response:
  • period – Type: uint32, 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 set_touch_state_callback_configuration.

Callbacks

BrickletMultiTouchV2.CALLBACK_TOUCH_STATE
Function ID:
  • 4
Response:
  • state – Type: bool[13]

Returns the current touch state, see get_touch_state for information about the state.

This callback is triggered every time the touch state changes with a given period (see set_touch_state_callback_configuration)