Go - RS232 Bricklet¶

Loopback¶

Download (example_loopback.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/rs232_bricklet"
)

// For this example connect the RX1 and TX pin to receive the send message

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your RS232 Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    rs232, _ := rs232_bricklet.New(UID, &ipcon) // Create device object.

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

    rs232.RegisterReadCallback(func(message [60]rune, length uint8) {
        fmt.Println("Message (Length %d) %s", length, string(message[:length]))
    })

    // Enable read callback
    rs232.EnableReadCallback()

    var chars [60]rune
    testChars := []rune{'t', 'e', 's', 't'}
    copy(chars[:], testChars)

    rs232.Write(chars, 4)

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

Basic Functions¶

func rs232_bricklet.New(uid string, ipcon *IPConnection) (device RS232Bricklet, err error)¶

Parameters:	uid – Type: string ipcon – Type: *IPConnection
Returns:	device – Type: RS232Bricklet err – Type: error

Creates a new RS232Bricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

device, err := rs232_bricklet.New("YOUR_DEVICE_UID", &ipcon)

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

func (*RS232Bricklet) Write(message [60]rune, length uint8) (written uint8, err error)¶

Parameters:	message – Type: [60]rune length – Type: uint8, Range: [0 to 60]
Returns:	written – Type: uint8, Range: [0 to 60] err – Type: error

Writes a string of up to 60 characters to the RS232 interface. The string can be binary data, ASCII or similar is not necessary.

The length of the string has to be given as an additional parameter.

The return value is the number of bytes that could be written.

See SetConfiguration() for configuration possibilities regarding baudrate, parity and so on.

func (*RS232Bricklet) Read() (message [60]rune, length uint8, err error)¶

Returns:	message – Type: [60]rune length – Type: uint8, Range: [0 to 60] err – Type: error

Returns the currently buffered message. The maximum length of message is 60. If the length is given as 0, there was no new data available.

Instead of polling with this function, you can also use callbacks. See EnableReadCallback() and RegisterReadCallback callback.

func (*RS232Bricklet) SetConfiguration(baudrate uint8, parity uint8, stopbits uint8, wordlength uint8, hardwareFlowcontrol uint8, softwareFlowcontrol uint8) (err error)¶

Parameters:	baudrate – Type: uint8, Range: See constants, Default: 11 parity – Type: uint8, Range: See constants, Default: 0 stopbits – Type: uint8, Range: See constants, Default: 1 wordlength – Type: uint8, Range: See constants, Default: 8 hardwareFlowcontrol – Type: uint8, Range: See constants, Default: 0 softwareFlowcontrol – Type: uint8, Range: See constants, Default: 0
Returns:	err – Type: error

Sets the configuration for the RS232 communication.

Hard-/Software flow control can either be on or off but not both simultaneously on.

The following constants are available for this function:

For baudrate:

• rs232_bricklet.Baudrate300 = 0
• rs232_bricklet.Baudrate600 = 1
• rs232_bricklet.Baudrate1200 = 2
• rs232_bricklet.Baudrate2400 = 3
• rs232_bricklet.Baudrate4800 = 4
• rs232_bricklet.Baudrate9600 = 5
• rs232_bricklet.Baudrate14400 = 6
• rs232_bricklet.Baudrate19200 = 7
• rs232_bricklet.Baudrate28800 = 8
• rs232_bricklet.Baudrate38400 = 9
• rs232_bricklet.Baudrate57600 = 10
• rs232_bricklet.Baudrate115200 = 11
• rs232_bricklet.Baudrate230400 = 12

For parity:

• rs232_bricklet.ParityNone = 0
• rs232_bricklet.ParityOdd = 1
• rs232_bricklet.ParityEven = 2
• rs232_bricklet.ParityForcedParity1 = 3
• rs232_bricklet.ParityForcedParity0 = 4

For stopbits:

• rs232_bricklet.Stopbits1 = 1
• rs232_bricklet.Stopbits2 = 2

For wordlength:

• rs232_bricklet.Wordlength5 = 5
• rs232_bricklet.Wordlength6 = 6
• rs232_bricklet.Wordlength7 = 7
• rs232_bricklet.Wordlength8 = 8

For hardwareFlowcontrol:

• rs232_bricklet.HardwareFlowcontrolOff = 0
• rs232_bricklet.HardwareFlowcontrolOn = 1

For softwareFlowcontrol:

• rs232_bricklet.SoftwareFlowcontrolOff = 0
• rs232_bricklet.SoftwareFlowcontrolOn = 1

func (*RS232Bricklet) GetConfiguration() (baudrate uint8, parity uint8, stopbits uint8, wordlength uint8, hardwareFlowcontrol uint8, softwareFlowcontrol uint8, err error)¶

Returns:	baudrate – Type: uint8, Range: See constants, Default: 11 parity – Type: uint8, Range: See constants, Default: 0 stopbits – Type: uint8, Range: See constants, Default: 1 wordlength – Type: uint8, Range: See constants, Default: 8 hardwareFlowcontrol – Type: uint8, Range: See constants, Default: 0 softwareFlowcontrol – Type: uint8, Range: See constants, Default: 0 err – Type: error

Returns the configuration as set by SetConfiguration().

The following constants are available for this function:

For baudrate:

• rs232_bricklet.Baudrate300 = 0
• rs232_bricklet.Baudrate600 = 1
• rs232_bricklet.Baudrate1200 = 2
• rs232_bricklet.Baudrate2400 = 3
• rs232_bricklet.Baudrate4800 = 4
• rs232_bricklet.Baudrate9600 = 5
• rs232_bricklet.Baudrate14400 = 6
• rs232_bricklet.Baudrate19200 = 7
• rs232_bricklet.Baudrate28800 = 8
• rs232_bricklet.Baudrate38400 = 9
• rs232_bricklet.Baudrate57600 = 10
• rs232_bricklet.Baudrate115200 = 11
• rs232_bricklet.Baudrate230400 = 12

For parity:

• rs232_bricklet.ParityNone = 0
• rs232_bricklet.ParityOdd = 1
• rs232_bricklet.ParityEven = 2
• rs232_bricklet.ParityForcedParity1 = 3
• rs232_bricklet.ParityForcedParity0 = 4

For stopbits:

• rs232_bricklet.Stopbits1 = 1
• rs232_bricklet.Stopbits2 = 2

For wordlength:

• rs232_bricklet.Wordlength5 = 5
• rs232_bricklet.Wordlength6 = 6
• rs232_bricklet.Wordlength7 = 7
• rs232_bricklet.Wordlength8 = 8

For hardwareFlowcontrol:

• rs232_bricklet.HardwareFlowcontrolOff = 0
• rs232_bricklet.HardwareFlowcontrolOn = 1

For softwareFlowcontrol:

• rs232_bricklet.SoftwareFlowcontrolOff = 0
• rs232_bricklet.SoftwareFlowcontrolOn = 1

func (*RS232Bricklet) SetBreakCondition(breakTime uint16) (err error)¶

Parameters:	breakTime – Type: uint16, Unit: 1 ms, Range: [0 to 216 - 1]
Returns:	err – Type: error

Sets a break condition (the TX output is forced to a logic 0 state). The parameter sets the hold-time of the break condition.

New in version 2.0.2 (Plugin).

Advanced Functions¶

func (*RS232Bricklet) GetIdentity() (uid string, connectedUid string, position rune, hardwareVersion [3]uint8, firmwareVersion [3]uint8, deviceIdentifier uint16, err error)¶

Returns:

uid – Type: string, Length: up to 8 connectedUid – Type: string, Length: up to 8 position – Type: rune, Range: ['a' to 'h', 'i', 'z'] hardwareVersion – Type: [3]uint8 0: major – Type: uint8, Range: [0 to 255] 1: minor – Type: uint8, Range: [0 to 255] 2: revision – Type: uint8, Range: [0 to 255] firmwareVersion – Type: [3]uint8 0: major – Type: uint8, Range: [0 to 255] 1: minor – Type: uint8, Range: [0 to 255] 2: revision – Type: uint8, Range: [0 to 255] deviceIdentifier – Type: uint16, Range: [0 to 216 - 1] err – Type: 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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as 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¶

func (*RS232Bricklet) EnableReadCallback() (err error)¶

Returns:	err – Type: error

Enables the RegisterReadCallback callback.

By default the callback is disabled.

func (*RS232Bricklet) DisableReadCallback() (err error)¶

Returns:	err – Type: error

Disables the RegisterReadCallback callback.

By default the callback is disabled.

func (*RS232Bricklet) IsReadCallbackEnabled() (enabled bool, err error)¶

Returns:	enabled – Type: bool, Default: false err – Type: error

Returns true if the RegisterReadCallback callback is enabled, false otherwise.

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 with the corresponding Deregister*Callback function.

func (*RS232Bricklet) RegisterReadCallback(func(message [60]rune, length uint8)) (registrationId uint64)¶

Callback Parameters:	message – Type: [60]rune length – Type: uint8, Range: [1 to 60]
Returns:	registrationId – Type: uint64

This callback is called if new data is available. The message has a maximum size of 60 characters. The actual length of the message is given in addition.

To enable this callback, use EnableReadCallback().

func (*RS232Bricklet) RegisterErrorCallback(func(error uint8)) (registrationId uint64)¶

Callback Parameters:	error – Type: uint8, Range: See constants
Returns:	registrationId – Type: uint64

This callback is called if an error occurs. Possible errors are overrun, parity or framing error.

The following constants are available for this function:

For error:

• rs232_bricklet.ErrorOverrun = 1
• rs232_bricklet.ErrorParity = 2
• rs232_bricklet.ErrorFraming = 4

New in version 2.0.1 (Plugin).

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.

func (*RS232Bricklet) GetAPIVersion() (apiVersion [3]uint8, err error)¶

Returns:	apiVersion – Type: [3]uint8 0: major – Type: uint8, Range: [0 to 255] 1: minor – Type: uint8, Range: [0 to 255] 2: revision – Type: uint8, Range: [0 to 255] err – Type: error

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.

func (*RS232Bricklet) GetResponseExpected(functionId uint8) (responseExpected bool, err error)¶

Parameters:	functionId – Type: uint8, Range: See constants
Returns:	responseExpected – Type: bool err – Type: 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:

For functionId:

• rs232_bricklet.FunctionEnableReadCallback = 3
• rs232_bricklet.FunctionDisableReadCallback = 4
• rs232_bricklet.FunctionSetConfiguration = 6
• rs232_bricklet.FunctionSetBreakCondition = 10

func (*RS232Bricklet) SetResponseExpected(functionId uint8, responseExpected bool) (err error)¶

Parameters:	functionId – Type: uint8, Range: See constants responseExpected – Type: bool
Returns:	err – Type: 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:

For functionId:

• rs232_bricklet.FunctionEnableReadCallback = 3
• rs232_bricklet.FunctionDisableReadCallback = 4
• rs232_bricklet.FunctionSetConfiguration = 6
• rs232_bricklet.FunctionSetBreakCondition = 10

func (*RS232Bricklet) SetResponseExpectedAll(responseExpected bool) (err error)¶

Parameters:	responseExpected – Type: bool
Returns:	err – Type: error

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

Constants¶

rs232_bricklet.DeviceIdentifier¶

This constant is used to identify a RS232 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.

rs232_bricklet.DeviceDisplayName¶

This constant represents the human readable name of a RS232 Bricklet.