Software / API Bindings / Python / API Reference and Examples / Bricklets (Discontinued) / IO-4 Bricklet

Python - IO-4 Bricklet¶

This is the description of the Python API bindings for the IO-4 Bricklet. General information and technical specifications for the IO-4 Bricklet are summarized in its hardware description.

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

Examples¶

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

Input¶

Download (example_input.py)

#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your IO-4 Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_io4 import BrickletIO4

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    io = BrickletIO4(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Get current value as bitmask
    value_mask = io.get_value()
    print("Value Mask: " + format(value_mask, "04b"))

    input("Press key to exit\n") # Use raw_input() in Python 2
    ipcon.disconnect()

Output¶

Download (example_output.py)

#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your IO-4 Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_io4 import BrickletIO4

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    io = BrickletIO4(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Set pin 1 to output low
    io.set_configuration(1 << 1, "o", False)

    # Set pin 2 and 3 to output high
    io.set_configuration((1 << 2) | (1 << 3), "o", True)

    input("Press key to exit\n") # Use raw_input() in Python 2
    ipcon.disconnect()

Interrupt¶

Download (example_interrupt.py)

#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your IO-4 Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_io4 import BrickletIO4

# Callback function for interrupt callback
def cb_interrupt(interrupt_mask, value_mask):
    print("Interrupt Mask: " + format(interrupt_mask, "04b"))
    print("Value Mask: " + format(value_mask, "04b"))
    print("")

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    io = BrickletIO4(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Register interrupt callback to function cb_interrupt
    io.register_callback(io.CALLBACK_INTERRUPT, cb_interrupt)

    # Enable interrupt on pin 0
    io.set_interrupt(1 << 0)

    input("Press key to exit\n") # Use raw_input() in Python 2
    ipcon.disconnect()

API¶

Generally, every function of the Python bindings can throw an tinkerforge.ip_connection.Error exception that has a value and a description property. value can have different values:

Error.TIMEOUT = -1
Error.NOT_ADDED = -6 (unused since Python bindings version 2.0.0)
Error.ALREADY_CONNECTED = -7
Error.NOT_CONNECTED = -8
Error.INVALID_PARAMETER = -9
Error.NOT_SUPPORTED = -10
Error.UNKNOWN_ERROR_CODE = -11
Error.STREAM_OUT_OF_SYNC = -12
Error.INVALID_UID = -13
Error.NON_ASCII_CHAR_IN_SECRET = -14
Error.WRONG_DEVICE_TYPE = -15
Error.DEVICE_REPLACED = -16
Error.WRONG_RESPONSE_LENGTH = -17

All functions listed below are thread-safe.

Basic Functions¶

BrickletIO4(uid, ipcon)¶

Parameters:	uid – Type: str ipcon – Type: IPConnection
Returns:	io4 – Type: BrickletIO4

Creates an object with the unique device ID uid:

io4 = BrickletIO4("YOUR_DEVICE_UID", ipcon)

This object can then be used after the IP Connection is connected.

BrickletIO4.set_value(value_mask)¶

Parameters:	value_mask – Type: int, Range: [0 to 15]
Returns:	None

Sets the output value (high or low) with a bitmask (4bit). A 1 in the bitmask means high and a 0 in the bitmask means low.

For example: The value 3 or 0b0011 will turn the pins 0-1 high and the pins 2-3 low.

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

Note

This function does nothing for pins that are configured as input. Pull-up resistors can be switched on with set_configuration().

BrickletIO4.get_value()¶

Returns:	value_mask – Type: int, Range: [0 to 15]

Returns a bitmask of the values that are currently measured. This function works if the pin is configured to input as well as if it is configured to output.

BrickletIO4.set_configuration(selection_mask, direction, value)¶

Parameters:	selection_mask – Type: int, Range: [0 to 15] direction – Type: chr, Range: See constants, Default: "i" value – Type: bool, Default: True
Returns:	None

Configures the value and direction of the specified pins. 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:

(15, 'i', true) or (0b1111, 'i', true) will set all pins of as input pull-up.
(8, 'i', false) or (0b1000, 'i', false) will set pin 3 of as input default (floating if nothing is connected).
(3, 'o', false) or (0b0011, 'o', false) will set pins 0 and 1 as output low.
(4, 'o', true) or (0b0100, 'o', true) will set pin 2 of as output high.

Running monoflop timers for the specified pins will be aborted if this function is called.

The following constants are available for this function:

For direction:

BrickletIO4.DIRECTION_IN = "i"
BrickletIO4.DIRECTION_OUT = "o"

BrickletIO4.get_configuration()¶

Return Object:	direction_mask – Type: int, Range: [0 to 15] value_mask – Type: int, Range: [0 to 15]

Returns a value bitmask and a direction bitmask. A 1 in the direction bitmask means input and a 0 in the bitmask means output.

For example: A return value of (3, 5) or (0b0011, 0b0101) for direction and value means that:

pin 0 is configured as input pull-up,
pin 1 is configured as input default,
pin 2 is configured as output high and
pin 3 is are configured as output low.

BrickletIO4.get_edge_count(pin, reset_counter)¶

Parameters:	pin – Type: int, Range: [0 to 3] reset_counter – Type: bool
Returns:	count – Type: int, Range: [0 to 2³² - 1]

Returns the current value of the edge counter for the selected pin. You can configure the edges that are counted with set_edge_count_config().

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

New in version 2.0.1 (Plugin).

Advanced Functions¶

BrickletIO4.set_monoflop(selection_mask, value_mask, time)¶

Parameters:	selection_mask – Type: int, Range: [0 to 15] value_mask – Type: int, Range: [0 to 15] time – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1]
Returns:	None

Configures a monoflop of the pins specified by the first parameter as 4 bit long bitmask. The specified pins must be configured for output. Non-output pins will be ignored.

The second parameter is a bitmask with the desired value of the specified output pins. A 1 in the bitmask means high and a 0 in the bitmask means low.

The third parameter indicates the time that the pins should hold the value.

If this function is called with the parameters (9, 1, 1500) or (0b1001, 0b0001, 1500): Pin 0 will get high and pin 3 will get low. In 1.5s pin 0 will get low and pin 3 will get high again.

A monoflop can be used as a fail-safe mechanism. For example: Lets assume you have a RS485 bus and an IO-4 Bricklet connected to one of the slave stacks. You can now call this function every second, with a time parameter of two seconds and pin 0 set to high. Pin 0 will be high all the time. If now the RS485 connection is lost, then pin 0 will get low in at most two seconds.

BrickletIO4.get_monoflop(pin)¶

Parameters:	pin – Type: int, Range: [0 to 3]
Return Object:	value – Type: int, Range: [0 to 1] 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 pin) the current value and the time as set by 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.

BrickletIO4.set_selected_values(selection_mask, value_mask)¶

Parameters:	selection_mask – Type: int, Range: [0 to 15] value_mask – Type: int, Range: [0 to 15]
Returns:	None

Sets the output value (high or low) with a bitmask, according to the selection mask. The bitmask is 4 bit long, true refers to high and false refers to low.

For example: The parameters (9, 4) or (0b0110, 0b0100) will turn pin 1 low and pin 2 high, pin 0 and 3 will remain untouched.

Running monoflop timers for the selected pins will be aborted if this function is called.

Note

This function does nothing for pins that are configured as input. Pull-up resistors can be switched on with set_configuration().

BrickletIO4.set_edge_count_config(selection_mask, edge_type, debounce)¶

Parameters:	selection_mask – Type: int, Range: [0 to 15] edge_type – Type: int, Range: See constants, Default: 0 debounce – Type: int, Unit: 1 ms, Range: [0 to 255], Default: 100
Returns:	None

Configures the edge counter for the selected pins.

The edge type parameter configures if rising edges, falling edges or both are counted if the pin is configured for input. Possible edge types are:

0 = rising (default)
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.

The following constants are available for this function:

For edge_type:

BrickletIO4.EDGE_TYPE_RISING = 0
BrickletIO4.EDGE_TYPE_FALLING = 1
BrickletIO4.EDGE_TYPE_BOTH = 2

New in version 2.0.1 (Plugin).

BrickletIO4.get_edge_count_config(pin)¶

Parameters:	pin – Type: int, Range: [0 to 3]
Return Object:	edge_type – Type: int, Range: See constants, Default: 0 debounce – Type: int, Unit: 1 ms, Range: [0 to 255], Default: 100

Returns the edge type and debounce time for the selected pin as set by set_edge_count_config().

The following constants are available for this function:

For edge_type:

BrickletIO4.EDGE_TYPE_RISING = 0
BrickletIO4.EDGE_TYPE_FALLING = 1
BrickletIO4.EDGE_TYPE_BOTH = 2

New in version 2.0.1 (Plugin).

BrickletIO4.get_identity()¶

Return Object:

Return Object:	uid – Type: str, Length: up to 8 connected_uid – Type: str, Length: up to 8 position – Type: chr, 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]

uid – Type: str, Length: up to 8
connected_uid – Type: str, Length: up to 8
position – Type: chr, 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]

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. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions¶

BrickletIO4.register_callback(callback_id, function)¶

Parameters:	callback_id – Type: int function – Type: callable
Returns:	None

Registers the given function with the given callback_id.

The available callback IDs with corresponding function signatures are listed below.

BrickletIO4.set_debounce_period(debounce)¶

Parameters:	debounce – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100
Returns:	None

Sets the debounce period of the CALLBACK_INTERRUPT callback.

For example: If you set this value to 100, you will get the interrupt maximal every 100ms. This is necessary if something that bounces is connected to the IO-4 Bricklet, such as a button.

BrickletIO4.get_debounce_period()¶

Returns:	debounce – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100

Returns the debounce period as set by set_debounce_period().

BrickletIO4.set_interrupt(interrupt_mask)¶

Parameters:	interrupt_mask – Type: int, Range: [0 to 15]
Returns:	None

Sets the pins on which an interrupt is activated with a bitmask. Interrupts are triggered on changes of the voltage level of the pin, i.e. changes from high to low and low to high.

For example: An interrupt bitmask of 10 or 0b1010 will enable the interrupt for pins 1 and 3.

The interrupt is delivered with the CALLBACK_INTERRUPT callback.

BrickletIO4.get_interrupt()¶

Returns:	interrupt_mask – Type: int, Range: [0 to 15]

Returns the interrupt bitmask as set by set_interrupt().

Callbacks¶

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the register_callback() function of the device object. The first parameter is the callback ID and the second parameter the callback function:

def my_callback(param):
    print(param)

io4.register_callback(BrickletIO4.CALLBACK_EXAMPLE, my_callback)

The available constants with inherent number and type of parameters 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.

BrickletIO4.CALLBACK_INTERRUPT¶

Callback Parameters:	interrupt_mask – Type: int, Range: [0 to 15] value_mask – Type: int, Range: [0 to 15]

This callback is triggered whenever a change of the voltage level is detected on pins where the interrupt was activated with set_interrupt().

The values are a bitmask that specifies which interrupts occurred and the current value bitmask.

For example:

(1, 1) or (0b0001, 0b0001) means that an interrupt on pin 0 occurred and currently pin 0 is high and pins 1-3 are low.
(9, 14) or (0b1001, 0b1110) means that interrupts on pins 0 and 3 occurred and currently pin 0 is low and pins 1-3 are high.

BrickletIO4.CALLBACK_MONOFLOP_DONE¶

Callback Parameters:	selection_mask – Type: int, Range: [0 to 15] value_mask – Type: int, Range: [0 to 15]

This callback is triggered whenever a monoflop timer reaches 0. The parameters contain the involved pins and the current value of the pins (the value after the monoflop).

Virtual Functions¶

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

BrickletIO4.get_api_version()¶

Return Object:	api_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]

Returns the version of the API definition 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.

BrickletIO4.get_response_expected(function_id)¶

Parameters:	function_id – Type: int, Range: See constants
Returns:	response_expected – Type: bool

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 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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

BrickletIO4.FUNCTION_SET_VALUE = 1
BrickletIO4.FUNCTION_SET_CONFIGURATION = 3
BrickletIO4.FUNCTION_SET_DEBOUNCE_PERIOD = 5
BrickletIO4.FUNCTION_SET_INTERRUPT = 7
BrickletIO4.FUNCTION_SET_MONOFLOP = 10
BrickletIO4.FUNCTION_SET_SELECTED_VALUES = 13
BrickletIO4.FUNCTION_SET_EDGE_COUNT_CONFIG = 15

BrickletIO4.set_response_expected(function_id, response_expected)¶

Parameters:	function_id – Type: int, Range: See constants response_expected – Type: bool
Returns:	None

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.

The following constants are available for this function:

For function_id:

BrickletIO4.FUNCTION_SET_VALUE = 1
BrickletIO4.FUNCTION_SET_CONFIGURATION = 3
BrickletIO4.FUNCTION_SET_DEBOUNCE_PERIOD = 5
BrickletIO4.FUNCTION_SET_INTERRUPT = 7
BrickletIO4.FUNCTION_SET_MONOFLOP = 10
BrickletIO4.FUNCTION_SET_SELECTED_VALUES = 13
BrickletIO4.FUNCTION_SET_EDGE_COUNT_CONFIG = 15

BrickletIO4.set_response_expected_all(response_expected)¶

Parameters:	response_expected – Type: bool
Returns:	None

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

Constants¶

BrickletIO4.DEVICE_IDENTIFIER¶

This constant is used to identify a IO-4 Bricklet.

The get_identity() function and the IPConnection.CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

BrickletIO4.DEVICE_DISPLAY_NAME¶: This constant represents the human readable name of a IO-4 Bricklet.