Modbus - Joystick Bricklet

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

API

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

Basic Functions

BrickletJoystick.get_position
Function ID:
  • 1
Request:
  • empty payload
Response:
  • x – Type: int16, Range: [-215 to 215 - 1]
  • y – Type: int16, Range: [-215 to 215 - 1]

Returns the position of the joystick. The value ranges between -100 and 100 for both axis. The middle position of the joystick is x=0, y=0. The returned values are averaged and calibrated (see calibrate).

If you want to get the position periodically, it is recommended to use the CALLBACK_POSITION callback and set the period with set_position_callback_period.

BrickletJoystick.is_pressed
Function ID:
  • 2
Request:
  • empty payload
Response:
  • pressed – Type: bool

Returns true if the button is pressed and false otherwise.

It is recommended to use the CALLBACK_PRESSED and CALLBACK_RELEASED callbacks to handle the button.

Advanced Functions

BrickletJoystick.get_analog_value
Function ID:
  • 3
Request:
  • empty payload
Response:
  • x – Type: uint16, Range: [0 to 216 - 1]
  • y – Type: uint16, Range: [0 to 216 - 1]

Returns the values as read by a 12-bit analog-to-digital converter. The values are between 0 and 4095 for both axis.

Note

The values returned by get_position are averaged over several samples to yield less noise, while get_analog_value gives back raw unfiltered analog values. The only reason to use get_analog_value is, if you need the full resolution of the analog-to-digital converter.

If you want the analog values periodically, it is recommended to use the CALLBACK_ANALOG_VALUE callback and set the period with set_analog_value_callback_period.

BrickletJoystick.calibrate
Function ID:
  • 4
Request:
  • empty payload
Response:
  • no response

Calibrates the middle position of the joystick. If your Joystick Bricklet does not return x=0 and y=0 in the middle position, call this function while the joystick is standing still in the middle position.

The resulting calibration will be saved on the EEPROM of the Joystick Bricklet, thus you only have to calibrate it once.

BrickletJoystick.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

BrickletJoystick.set_position_callback_period
Function ID:
  • 5
Request:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Response:
  • no response

Sets the period with which the CALLBACK_POSITION callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_POSITION callback is only triggered if the position has changed since the last triggering.

BrickletJoystick.get_position_callback_period
Function ID:
  • 6
Request:
  • empty payload
Response:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by set_position_callback_period.

BrickletJoystick.set_analog_value_callback_period
Function ID:
  • 7
Request:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Response:
  • no response

Sets the period with which the CALLBACK_ANALOG_VALUE callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_ANALOG_VALUE callback is only triggered if the analog values have changed since the last triggering.

BrickletJoystick.get_analog_value_callback_period
Function ID:
  • 8
Request:
  • empty payload
Response:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by set_analog_value_callback_period.

BrickletJoystick.set_position_callback_threshold
Function ID:
  • 9
Request:
  • option – Type: char, Range: See meanings, Default: 'x'
  • min_x – Type: int16, Range: [-215 to 215 - 1]
  • max_x – Type: int16, Range: [-215 to 215 - 1]
  • min_y – Type: int16, Range: [-215 to 215 - 1]
  • max_y – Type: int16, Range: [-215 to 215 - 1]
Response:
  • no response

Sets the thresholds for the CALLBACK_POSITION_REACHED callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the position is outside the min and max values
'i' Callback is triggered when the position is inside the min and max values
'<' Callback is triggered when the position is smaller than the min values (max is ignored)
'>' Callback is triggered when the position is greater than the min values (max is ignored)

The default value is ('x', 0, 0, 0, 0).

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletJoystick.get_position_callback_threshold
Function ID:
  • 10
Request:
  • empty payload
Response:
  • option – Type: char, Range: See meanings, Default: 'x'
  • min_x – Type: int16, Range: [-215 to 215 - 1]
  • max_x – Type: int16, Range: [-215 to 215 - 1]
  • min_y – Type: int16, Range: [-215 to 215 - 1]
  • max_y – Type: int16, Range: [-215 to 215 - 1]

Returns the threshold as set by set_position_callback_threshold.

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletJoystick.set_analog_value_callback_threshold
Function ID:
  • 11
Request:
  • option – Type: char, Range: See meanings, Default: 'x'
  • min_x – Type: uint16, Range: [0 to 216 - 1]
  • max_x – Type: uint16, Range: [0 to 216 - 1]
  • min_y – Type: uint16, Range: [0 to 216 - 1]
  • max_y – Type: uint16, Range: [0 to 216 - 1]
Response:
  • no response

Sets the thresholds for the CALLBACK_ANALOG_VALUE_REACHED callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the analog values are outside the min and max values
'i' Callback is triggered when the analog values are inside the min and max values
'<' Callback is triggered when the analog values are smaller than the min values (max is ignored)
'>' Callback is triggered when the analog values are greater than the min values (max is ignored)

The default value is ('x', 0, 0, 0, 0).

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletJoystick.get_analog_value_callback_threshold
Function ID:
  • 12
Request:
  • empty payload
Response:
  • option – Type: char, Range: See meanings, Default: 'x'
  • min_x – Type: uint16, Range: [0 to 216 - 1]
  • max_x – Type: uint16, Range: [0 to 216 - 1]
  • min_y – Type: uint16, Range: [0 to 216 - 1]
  • max_y – Type: uint16, Range: [0 to 216 - 1]

Returns the threshold as set by set_analog_value_callback_threshold.

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletJoystick.set_debounce_period
Function ID:
  • 13
Request:
  • debounce – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100
Response:
  • no response

Sets the period with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

BrickletJoystick.get_debounce_period
Function ID:
  • 14
Request:
  • empty payload
Response:
  • debounce – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by set_debounce_period.

Callbacks

BrickletJoystick.CALLBACK_POSITION
Function ID:
  • 15
Response:
  • x – Type: int16, Range: [-215 to 215 - 1]
  • y – Type: int16, Range: [-215 to 215 - 1]

This callback is triggered periodically with the period that is set by set_position_callback_period. The response value is the position of the joystick.

The CALLBACK_POSITION callback is only triggered if the position has changed since the last triggering.

BrickletJoystick.CALLBACK_ANALOG_VALUE
Function ID:
  • 16
Response:
  • x – Type: uint16, Range: [0 to 216 - 1]
  • y – Type: uint16, Range: [0 to 216 - 1]

This callback is triggered periodically with the period that is set by set_analog_value_callback_period. The response values are the analog values of the joystick.

The CALLBACK_ANALOG_VALUE callback is only triggered if the values have changed since the last triggering.

BrickletJoystick.CALLBACK_POSITION_REACHED
Function ID:
  • 17
Response:
  • x – Type: int16, Range: [-215 to 215 - 1]
  • y – Type: int16, Range: [-215 to 215 - 1]

This callback is triggered when the threshold as set by set_position_callback_threshold is reached. The response values are the position of the joystick.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by set_debounce_period.

BrickletJoystick.CALLBACK_ANALOG_VALUE_REACHED
Function ID:
  • 18
Response:
  • x – Type: uint16, Range: [0 to 216 - 1]
  • y – Type: uint16, Range: [0 to 216 - 1]

This callback is triggered when the threshold as set by set_analog_value_callback_threshold is reached. The response values are the analog values of the joystick.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by set_debounce_period.

BrickletJoystick.CALLBACK_PRESSED
Function ID:
  • 19
Response:
  • empty payload

This callback is triggered when the button is pressed.

BrickletJoystick.CALLBACK_RELEASED
Function ID:
  • 20
Response:
  • empty payload

This callback is triggered when the button is released.