Go - IO-4 Bricklet

This is the description of the Go 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 Go API bindings is part of their general description. Additional documentation can be found on godoc.org.

Examples

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

Input

Download (example_input.go)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/io4_bricklet"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your IO-4 Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    io, _ := io4_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Get current value as bitmask.
    valueMask, _ := io.GetValue()
    fmt.Printf("Value Mask: %b\n", valueMask)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

Output

Download (example_output.go)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/io4_bricklet"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your IO-4 Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    io, _ := io4_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Set pin 1 to output low
    io.SetConfiguration(1<<1, 'o', false)

    // Set pin 2 and 3 to output high
    io.SetConfiguration((1<<2)|(1<<3), 'o', true)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

Interrupt

Download (example_interrupt.go)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/io4_bricklet"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your IO-4 Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    io, _ := io4_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    io.RegisterInterruptCallback(func(interruptMask uint8, valueMask uint8) {
        fmt.Printf("Interrupt Mask: %b\n", interruptMask)
        fmt.Printf("Value Mask: %b\n", valueMask)
        fmt.Println()
    })

    // Enable interrupt on pin 0
    io.SetInterrupt(1 << 0)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

API

The IO-4 Bricklet API is defined in the package github.com/Tinkerforge/go-api-bindings/io4_bricklet

Nearly every function of the Go bindings can return an DeviceError, implementing the error interface. The error can have one of the following values:

  • DeviceErrorSuccess = 0
  • DeviceErrorInvalidParameter = 1
  • DeviceErrorFunctionNotSupported = 2
  • DeviceErrorUnknownError = 3

which correspond to the values returned from Bricks and Bricklets.

All functions listed below are thread-safe.

Basic Functions

func io4_bricklet.New(uid string, ipcon *IPConnection) (device IO4Bricklet, err error)

Creates a new IO4Bricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

device, err := io4_bricklet.New("YOUR_DEVICE_UID", &ipcon)

This device object can be used after the IPConnection has been connected (see examples above).

func (*IO4Bricklet) SetValue(valueMask uint8) (err error)

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 SetConfiguration().

func (*IO4Bricklet) GetValue() (valueMask uint8, err error)

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.

func (*IO4Bricklet) SetConfiguration(selectionMask uint8, direction Direction, value bool) (err error)

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 default configuration is input with pull-up.

The following constants are available for this function:

  • io4_bricklet.DirectionIn = 'i'
  • io4_bricklet.DirectionOut = 'o'
func (*IO4Bricklet) GetConfiguration() (directionMask uint8, valueMask uint8, err error)

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.
func (*IO4Bricklet) GetEdgeCount(pin uint8, resetCounter bool) (count uint32, err error)

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

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

func (*IO4Bricklet) SetMonoflop(selectionMask uint8, valueMask uint8, time uint32) (err error)

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 (in ms) 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.

func (*IO4Bricklet) GetMonoflop(pin uint8) (value uint8, time uint32, timeRemaining uint32, err error)

Returns (for the given pin) the current value and the time as set by SetMonoflop() 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.

func (*IO4Bricklet) SetSelectedValues(selectionMask uint8, valueMask uint8) (err error)

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 SetConfiguration().

func (*IO4Bricklet) SetEdgeCountConfig(selectionMask uint8, edgeType EdgeType, debounce uint8) (err error)

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

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 constants are available for this function:

  • io4_bricklet.EdgeTypeRising = 0
  • io4_bricklet.EdgeTypeFalling = 1
  • io4_bricklet.EdgeTypeBoth = 2

New in version 2.0.1 (Plugin).

func (*IO4Bricklet) GetEdgeCountConfig(pin uint8) (edgeType EdgeType, debounce uint8, err error)

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

The following constants are available for this function:

  • io4_bricklet.EdgeTypeRising = 0
  • io4_bricklet.EdgeTypeFalling = 1
  • io4_bricklet.EdgeTypeBoth = 2

New in version 2.0.1 (Plugin).

func (*IO4Bricklet) GetAPIVersion() (apiVersion [3]uint8, err error)

Returns the version of the API definition (major, minor, revision) 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.

func (*IO4Bricklet) GetResponseExpected(functionId Function) (responseExpected bool, err error)

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 SetResponseExpected(). 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 send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

  • io4_bricklet.FunctionSetValue = 1
  • io4_bricklet.FunctionSetConfiguration = 3
  • io4_bricklet.FunctionSetDebouncePeriod = 5
  • io4_bricklet.FunctionSetInterrupt = 7
  • io4_bricklet.FunctionSetMonoflop = 10
  • io4_bricklet.FunctionSetSelectedValues = 13
  • io4_bricklet.FunctionSetEdgeCountConfig = 15
func (*IO4Bricklet) SetResponseExpected(functionId Function, responseExpected bool) (err error)

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.

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

The following constants are available for this function:

  • io4_bricklet.FunctionSetValue = 1
  • io4_bricklet.FunctionSetConfiguration = 3
  • io4_bricklet.FunctionSetDebouncePeriod = 5
  • io4_bricklet.FunctionSetInterrupt = 7
  • io4_bricklet.FunctionSetMonoflop = 10
  • io4_bricklet.FunctionSetSelectedValues = 13
  • io4_bricklet.FunctionSetEdgeCountConfig = 15
func (*IO4Bricklet) SetResponseExpectedAll(responseExpected bool) (err error)

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

func (*IO4Bricklet) GetIdentity() (uid string, connectedUid string, position rune, hardwareVersion [3]uint8, firmwareVersion [3]uint8, deviceIdentifier uint16, err error)

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

Callback Configuration Functions

func (*IO4Bricklet) SetDebouncePeriod(debounce uint32) (err error)

Sets the debounce period of the RegisterInterruptCallback callback in ms.

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.

The default value is 100.

func (*IO4Bricklet) GetDebouncePeriod() (debounce uint32, err error)

Returns the debounce period as set by SetDebouncePeriod().

func (*IO4Bricklet) SetInterrupt(interruptMask uint8) (err error)

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 RegisterInterruptCallback callback.

func (*IO4Bricklet) GetInterrupt() (interruptMask uint8, err error)

Returns the interrupt bitmask as set by SetInterrupt().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding Register*Callback function, which returns a unique callback ID. This ID 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.

func (*IO4Bricklet) RegisterInterruptCallback(func(interruptMask uint8, valueMask uint8)) (registrationId uint64)

A callback can be registered for this event with the RegisterInterruptCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterInterruptCallback(registrationId uint64) function.

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

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.
func (*IO4Bricklet) RegisterMonoflopDoneCallback(func(selectionMask uint8, valueMask uint8)) (registrationId uint64)

A callback can be registered for this event with the RegisterMonoflopDoneCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterMonoflopDoneCallback(registrationId uint64) function.

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

Constants

io4_bricklet.DeviceIdentifier

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

The GetIdentity() function and the (*IPConnection) RegisterEnumerateCallback callback of the IPConnection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

io4_bricklet.DeviceDisplayName

This constant represents the human readable name of a IO-4 Bricklet.