Go - IO-4 Bricklet 2.0

This is the description of the Go API bindings for the IO-4 Bricklet 2.0. General information and technical specifications for the IO-4 Bricklet 2.0 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).

Interrupt

Download (example_interrupt.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/io4_v2_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 2.0.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    io, _ := io4_v2_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.RegisterInputValueCallback(func(channel uint8, changed bool, value bool) {
        fmt.Printf("Channel: %d\n", channel)
        fmt.Printf("Changed: %s\n", changed)
        fmt.Printf("Value: %s\n", value)
        fmt.Println()
    })

    // Set period for input value (channel 1) callback to 0.5s (500ms).
    io.SetInputValueCallbackConfiguration(1, 500, false)

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

Output

Download (example_output.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/io4_v2_bricklet"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "time"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your IO-4 Bricklet 2.0.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    io, _ := io4_v2_bricklet.New(UID, &ipcon) // Create device object.

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

    // Configure channel 3 as output low
    io.SetConfiguration(3, 'o', false)

    // Set channel 3 alternating high/low 10 times with 100 ms delay
    for i := 0; i < 10; i++ {
        time.Sleep(100 * time.Millisecond)
        io.SetSelectedValue(3, true)
        time.Sleep(100 * time.Millisecond)
        io.SetSelectedValue(3, false)
    }

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

API

The IO-4 Bricklet 2.0 API is defined in the package github.com/Tinkerforge/go-api-bindings/io4_v2_bricklet

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

  • BrickletErrorSuccess = 0
  • BrickletErrorInvalidParameter = 1
  • BrickletErrorFunctionNotSupported = 2
  • BrickletErrorUnknownError = 3

which correspond to the values returned from Bricks and Bricklets.

All functions listed below are thread-safe.

Basic Functions

func NewIO4V2Bricklet(uid string, ipcon *IPConnection)(device IO4V2Bricklet, err error)

Creates a new IO4V2Bricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

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

func (*IO4V2Bricklet)SetValue(value [4]bool)(err error)

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

Use (*IO4V2Bricklet) SetSelectedValue to change only one output channel state.

For example: (True, True, False, False) will turn the channels 0-1 high and the channels 2-3 low.

All running monoflop timers and PWMs 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 (*IO4V2Bricklet) SetConfiguration.

func (*IO4V2Bricklet)GetValue()(value [4]bool, err error)

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.

func (*IO4V2Bricklet)SetSelectedValue(channel uint8, value bool)(err error)

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

A running monoflop timer or PWM 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 (*IO4V2Bricklet) SetConfiguration.

func (*IO4V2Bricklet)SetConfiguration(channel uint8, direction Direction, value bool)(err error)

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

The default configuration is input with pull-up.

The following constants are available for this function:

  • DirectionIn = 'i'
  • DirectionOut = 'o'
func (*IO4V2Bricklet)GetConfiguration(channel uint8)(direction Direction, value bool, err error)

Returns the channel configuration as set by (*IO4V2Bricklet) SetConfiguration.

The following constants are available for this function:

  • DirectionIn = 'i'
  • DirectionOut = 'o'

Advanced Functions

func (*IO4V2Bricklet)SetMonoflop(channel uint8, value bool, time uint32)(err error)

The first parameter is the desired state of the channel (true means output high and false means output low). The second parameter indicates the time (in ms) that the channel should hold the state.

If this function is called with the parameters (true, 1500): The channel will turn on and in 1.5s it will turn off again.

A PWM for the selected channel will be aborted if this function is called.

A monoflop can be used as a failsafe mechanism. For example: Lets assume you have a RS485 bus and a IO-4 Bricklet 2.0 is connected to one of the slave stacks. You can now call this function every second, with a time parameter of two seconds. The channel will be high all the time. If now the RS485 connection is lost, the channel will turn low in at most two seconds.

func (*IO4V2Bricklet)GetMonoflop(channel uint8)(value bool, time uint32, timeRemaining uint32, err error)

Returns (for the given channel) the current value and the time as set by (*IO4V2Bricklet) 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 (*IO4V2Bricklet)GetEdgeCount(channel uint8, resetCounter bool)(count uint32, err error)

Returns the current value of the edge counter for the selected channel. You can configure the edges that are counted with (*IO4V2Bricklet) SetEdgeCountConfiguration.

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

func (*IO4V2Bricklet)SetEdgeCountConfiguration(channel uint8, edgeType EdgeType, debounce uint8)(err error)

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 constants are available for this function:

  • EdgeTypeRising = 0
  • EdgeTypeFalling = 1
  • EdgeTypeBoth = 2
func (*IO4V2Bricklet)GetEdgeCountConfiguration(channel uint8)(edgeType EdgeType, debounce uint8, err error)

Returns the edge type and debounce time for the selected channel as set by (*IO4V2Bricklet) SetEdgeCountConfiguration.

The following constants are available for this function:

  • EdgeTypeRising = 0
  • EdgeTypeFalling = 1
  • EdgeTypeBoth = 2
func (*IO4V2Bricklet)SetPWMConfiguration(channel uint8, frequency uint32, dutyCycle uint16)(err error)

Activates a PWM for the given channel with the frequency given in 1/10Hz and the duty cycle given in 1/100%.

You need to set the channel to output before you call this function, otherwise it will be ignored. To turn the PWM off again, you can set the frequency to 0 or any other function that changes a value of the channel (e.g. (*IO4V2Bricklet) SetSelectedValue).

The maximum frequency value is 320000000 (32MHz). The maximum duty cycle value is 10000 (100%).

A running monoflop timer for the given channel will be aborted if this function is called.

The default values are 0, 0.

func (*IO4V2Bricklet)GetPWMConfiguration(channel uint8)(frequency uint32, dutyCycle uint16, err error)

Returns the PWM configuration as set by (*IO4V2Bricklet) SetPWMConfiguration.

func (*IO4V2Bricklet)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 (*IO4V2Bricklet)GetResponseExpected(functionId uint8)(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 (*IO4V2Bricklet) 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.

See (*IO4V2Bricklet) SetResponseExpected for the list of function ID constants available for this function.

func (*IO4V2Bricklet)SetResponseExpected(functionId uint8, 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 function ID constants are available for this function:

  • FunctionSetValue = 1
  • FunctionSetSelectedValue = 3
  • FunctionSetConfiguration = 4
  • FunctionSetInputValueCallbackConfiguration = 6
  • FunctionSetAllInputValueCallbackConfiguration = 8
  • FunctionSetMonoflop = 10
  • FunctionSetEdgeCountConfiguration = 13
  • FunctionSetPWMConfiguration = 15
  • FunctionSetWriteFirmwarePointer = 237
  • FunctionSetStatusLEDConfig = 239
  • FunctionReset = 243
  • FunctionWriteUID = 248
func (*IO4V2Bricklet)SetResponseExpectedAll(responseExpected bool)(err error)

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

func (*IO4V2Bricklet)GetSPITFPErrorCount()(errorCountAckChecksum uint32, errorCountMessageChecksum uint32, errorCountFrame uint32, errorCountOverflow uint32, err error)

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.

func (*IO4V2Bricklet)SetBootloaderMode(mode BootloaderMode)(status BootloaderStatus, err error)

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 constants are available for this function:

  • BootloaderModeBootloader = 0
  • BootloaderModeFirmware = 1
  • BootloaderModeBootloaderWaitForReboot = 2
  • BootloaderModeFirmwareWaitForReboot = 3
  • BootloaderModeFirmwareWaitForEraseAndReboot = 4
  • BootloaderStatusOK = 0
  • BootloaderStatusInvalidMode = 1
  • BootloaderStatusNoChange = 2
  • BootloaderStatusEntryFunctionNotPresent = 3
  • BootloaderStatusDeviceIdentifierIncorrect = 4
  • BootloaderStatusCRCMismatch = 5
func (*IO4V2Bricklet)GetBootloaderMode()(mode BootloaderMode, err error)

Returns the current bootloader mode, see (*IO4V2Bricklet) SetBootloaderMode.

The following constants are available for this function:

  • BootloaderModeBootloader = 0
  • BootloaderModeFirmware = 1
  • BootloaderModeBootloaderWaitForReboot = 2
  • BootloaderModeFirmwareWaitForReboot = 3
  • BootloaderModeFirmwareWaitForEraseAndReboot = 4
func (*IO4V2Bricklet)SetWriteFirmwarePointer(pointer uint32)(err error)

Sets the firmware pointer for (*IO4V2Bricklet) WriteFirmware. 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.

func (*IO4V2Bricklet)WriteFirmware(data [64]uint8)(status uint8, err error)

Writes 64 Bytes of firmware at the position as written by (*IO4V2Bricklet) SetWriteFirmwarePointer 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.

func (*IO4V2Bricklet)SetStatusLEDConfig(config StatusLEDConfig)(err error)

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 constants are available for this function:

  • StatusLEDConfigOff = 0
  • StatusLEDConfigOn = 1
  • StatusLEDConfigShowHeartbeat = 2
  • StatusLEDConfigShowStatus = 3
func (*IO4V2Bricklet)GetStatusLEDConfig()(config StatusLEDConfig, err error)

Returns the configuration as set by (*IO4V2Bricklet) SetStatusLEDConfig

The following constants are available for this function:

  • StatusLEDConfigOff = 0
  • StatusLEDConfigOn = 1
  • StatusLEDConfigShowHeartbeat = 2
  • StatusLEDConfigShowStatus = 3
func (*IO4V2Bricklet)GetChipTemperature()(temperature int16, err error)

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.

func (*IO4V2Bricklet)Reset()(err error)

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!

func (*IO4V2Bricklet)WriteUID(uid uint32)(err error)

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.

func (*IO4V2Bricklet)ReadUID()(uid uint32, err error)

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

func (*IO4V2Bricklet)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 (*IO4V2Bricklet)SetInputValueCallbackConfiguration(channel uint8, period uint32, valueHasToChange bool)(err error)

This callback can be configured per channel.

The period in ms is the period with which the (*IO4V2Bricklet) RegisterInputValueCallback 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).

func (*IO4V2Bricklet)GetInputValueCallbackConfiguration(channel uint8)(period uint32, valueHasToChange bool, err error)

Returns the callback configuration for the given channel as set by (*IO4V2Bricklet) SetInputValueCallbackConfiguration.

func (*IO4V2Bricklet)SetAllInputValueCallbackConfiguration(period uint32, valueHasToChange bool)(err error)

The period in ms is the period with which the (*IO4V2Bricklet) RegisterAllInputValueCallback 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).

func (*IO4V2Bricklet)GetAllInputValueCallbackConfiguration()(period uint32, valueHasToChange bool, err error)

Returns the callback configuration as set by (*IO4V2Bricklet) SetAllInputValueCallbackConfiguration.

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 (*IO4V2Bricklet)RegisterInputValueCallback(func(channel uint8, changed bool, value bool))(registrationID uint64)

A callback can be registered for this event with the RegisterInputValueCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterInputValueCallback(registrationID uint64) function.

This callback is triggered periodically according to the configuration set by (*IO4V2Bricklet) SetInputValueCallbackConfiguration.

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.

func (*IO4V2Bricklet)RegisterAllInputValueCallback(func(changed [4]bool, value [4]bool))(registrationID uint64)

A callback can be registered for this event with the RegisterAllInputValueCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterAllInputValueCallback(registrationID uint64) function.

This callback is triggered periodically according to the configuration set by (*IO4V2Bricklet) SetAllInputValueCallbackConfiguration.

The callback parameters are the same as (*IO4V2Bricklet) GetValue. Additional the changed parameter is true if the value has changed since the last callback.

func (*IO4V2Bricklet)RegisterMonoflopDoneCallback(func(channel uint8, value bool))(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 channel and the current value of the channel (the value after the monoflop).

Constants

io4_v2_bricklet.DeviceIdentifier

This constant is used to identify a IO-4 Bricklet 2.0.

The (*IO4V2Bricklet) GetIdentity function and the (*IPConnection) RegisterEnumerateCallback callback of the IPConnection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

io4_v2_bricklet.DeviceDisplayName

This constant represents the human readable name of a IO-4 Bricklet 2.0.