Delphi/Lazarus - IO-4 Bricklet

This is the description of the Delphi/Lazarus 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 Delphi/Lazarus API bindings is part of their general description.

Examples

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

Input

Download (ExampleInput.pas)

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program ExampleInput;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletIO4;

type
  TExample = class
  private
    ipcon: TIPConnection;
    io: TBrickletIO4;
  public
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your IO-4 Bricklet }

var
  e: TExample;

procedure TExample.Execute;
var valueMask: byte;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  io := TBrickletIO4.Create(UID, ipcon);

  { Connect to brickd }
  ipcon.Connect(HOST, PORT);
  { Don't use device before ipcon is connected }

  { Get current value as bitmask }
  valueMask := io.GetValue;
  WriteLn(Format('Value Mask: %d', [valueMask]));

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

Output

Download (ExampleOutput.pas)

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program ExampleOutput;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletIO4;

type
  TExample = class
  private
    ipcon: TIPConnection;
    io: TBrickletIO4;
  public
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your IO-4 Bricklet }

var
  e: TExample;

procedure TExample.Execute;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  io := TBrickletIO4.Create(UID, ipcon);

  { Connect to brickd }
  ipcon.Connect(HOST, PORT);
  { Don't use device before ipcon is connected }

  { Set pin 1 to output low }
  io.SetConfiguration(1 shl 1, 'o', false);

  { Set pin 2 and 3 to output high }
  io.SetConfiguration((1 shl 2) or (1 shl 3), 'o', true);

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

Interrupt

Download (ExampleInterrupt.pas)

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program ExampleInterrupt;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletIO4;

type
  TExample = class
  private
    ipcon: TIPConnection;
    io: TBrickletIO4;
  public
    procedure InterruptCB(sender: TBrickletIO4; const interruptMask: byte;
                          const valueMask: byte);
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your IO-4 Bricklet }

var
  e: TExample;

{ Callback procedure for interrupt callback }
procedure TExample.InterruptCB(sender: TBrickletIO4; const interruptMask: byte;
                               const valueMask: byte);
begin
  WriteLn(Format('Interrupt Mask: %d', [interruptMask]));
  WriteLn(Format('Value Mask: %d', [valueMask]));
  WriteLn('');
end;

procedure TExample.Execute;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  io := TBrickletIO4.Create(UID, ipcon);

  { Connect to brickd }
  ipcon.Connect(HOST, PORT);
  { Don't use device before ipcon is connected }

  { Register interrupt callback to procedure InterruptCB }
  io.OnInterrupt := {$ifdef FPC}@{$endif}InterruptCB;

  { Enable interrupt on pin 0 }
  io.SetInterrupt(1 shl 0);

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

API

Since Delphi does not support multiple return values directly, we use the out keyword to return multiple values from a function.

All functions and procedures listed below are thread-safe.

Basic Functions

constructor TBrickletIO4.Create(const uid: string; ipcon: TIPConnection)

Creates an object with the unique device ID uid:

io4 := TBrickletIO4.Create('YOUR_DEVICE_UID', ipcon);

This object can then be used after the IP Connection is connected (see examples above).

procedure TBrickletIO4.SetValue(const valueMask: byte)

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.

function TBrickletIO4.GetValue: byte

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.

procedure TBrickletIO4.SetConfiguration(const selectionMask: byte; const direction: char; const value: boolean)

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:

  • BRICKLET_IO4_DIRECTION_IN = 'i'
  • BRICKLET_IO4_DIRECTION_OUT = 'o'
procedure TBrickletIO4.GetConfiguration(out directionMask: byte; out valueMask: byte)

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.
function TBrickletIO4.GetEdgeCount(const pin: byte; const resetCounter: boolean): longword

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

procedure TBrickletIO4.SetMonoflop(const selectionMask: byte; const valueMask: byte; const time: longword)

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.

procedure TBrickletIO4.GetMonoflop(const pin: byte; out value: byte; out time: longword; out timeRemaining: longword)

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.

procedure TBrickletIO4.SetSelectedValues(const selectionMask: byte; const valueMask: byte)

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.

procedure TBrickletIO4.SetEdgeCountConfig(const selectionMask: byte; const edgeType: byte; const debounce: byte)

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:

  • BRICKLET_IO4_EDGE_TYPE_RISING = 0
  • BRICKLET_IO4_EDGE_TYPE_FALLING = 1
  • BRICKLET_IO4_EDGE_TYPE_BOTH = 2

New in version 2.0.1 (Plugin).

procedure TBrickletIO4.GetEdgeCountConfig(const pin: byte; out edgeType: byte; out debounce: byte)

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

The following constants are available for this function:

  • BRICKLET_IO4_EDGE_TYPE_RISING = 0
  • BRICKLET_IO4_EDGE_TYPE_FALLING = 1
  • BRICKLET_IO4_EDGE_TYPE_BOTH = 2

New in version 2.0.1 (Plugin).

function TBrickletIO4.GetAPIVersion: array [0..2] of byte

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.

function TBrickletIO4.GetResponseExpected(const functionId: byte): boolean

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.

See SetResponseExpected for the list of function ID constants available for this function.

procedure TBrickletIO4.SetResponseExpected(const functionId: byte; const responseExpected: boolean)

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:

  • BRICKLET_IO4_FUNCTION_SET_VALUE = 1
  • BRICKLET_IO4_FUNCTION_SET_CONFIGURATION = 3
  • BRICKLET_IO4_FUNCTION_SET_DEBOUNCE_PERIOD = 5
  • BRICKLET_IO4_FUNCTION_SET_INTERRUPT = 7
  • BRICKLET_IO4_FUNCTION_SET_MONOFLOP = 10
  • BRICKLET_IO4_FUNCTION_SET_SELECTED_VALUES = 13
  • BRICKLET_IO4_FUNCTION_SET_EDGE_COUNT_CONFIG = 15
procedure TBrickletIO4.SetResponseExpectedAll(const responseExpected: boolean)

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

procedure TBrickletIO4.GetIdentity(out uid: string; out connectedUid: string; out position: char; out hardwareVersion: array [0..2] of byte; out firmwareVersion: array [0..2] of byte; out deviceIdentifier: word)

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

procedure TBrickletIO4.SetDebouncePeriod(const debounce: longword)

Sets the debounce period of the OnInterrupt 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.

function TBrickletIO4.GetDebouncePeriod: longword

Returns the debounce period as set by SetDebouncePeriod.

procedure TBrickletIO4.SetInterrupt(const interruptMask: byte)

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 OnInterrupt callback.

function TBrickletIO4.GetInterrupt: byte

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 by assigning a procedure to an callback property of the device object:

procedure TExample.MyCallback(sender: TBrickletIO4; const param: word);
begin
  WriteLn(param);
end;

io4.OnExample := {$ifdef FPC}@{$endif}example.MyCallback;

The available callback property and their 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.

property TBrickletIO4.OnInterrupt
procedure(sender: TBrickletIO4; const interruptMask: byte; const valueMask: byte) of object;

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.
property TBrickletIO4.OnMonoflopDone
procedure(sender: TBrickletIO4; const selectionMask: byte; const valueMask: byte) of object;

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).

Constants

const BRICKLET_IO4_DEVICE_IDENTIFIER

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

The GetIdentity function and the OnEnumerate callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

const BRICKLET_IO4_DEVICE_DISPLAY_NAME

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