Delphi/Lazarus - One Wire Bricklet

This is the description of the Delphi/Lazarus API bindings for the One Wire Bricklet. General information and technical specifications for the One Wire 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).

Read DS 18B 20Temperature

Download (ExampleReadDS18B20Temperature.pas)

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program ExampleReadDS18B20Temperature;

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

uses
  SysUtils, IPConnection, BrickletOneWire;

type
  TExample = class
  private
    ipcon: TIPConnection;
    ow: TBrickletOneWire;
  public
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your One Wire Bricklet }

var
  e: TExample;

procedure TExample.Execute;
var i: integer;
var t_low, t_high, status: byte;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  ow := TBrickletOneWire.Create(UID, ipcon);

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

  ow.WriteCommand(0, 78); { WRITE SCRATCHPAD }
  ow.Write(0); { ALARM H (unused) }
  ow.Write(0); { ALARM L (unused) }
  ow.Write(127); { CONFIGURATION: 12 bit mode }

  { Read temperature 10 times }
  for i := 0 to 9 do begin
    ow.WriteCommand(0, 68); { CONVERT T (start temperature conversion) }
    Sleep(1000); { Wait for conversion to finish }
    ow.WriteCommand(0, 190); { READ SCRATCHPAD }

    ow.Read(t_low, status);
    ow.Read(t_high, status);
    WriteLn('Temperature: %d °C', (t_low or (t_high shl 8)) / 16.0);
  end;

  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 TBrickletOneWire.Create(const uid: string; ipcon: TIPConnection)

Creates an object with the unique device ID uid:

oneWire := TBrickletOneWire.Create('YOUR_DEVICE_UID', ipcon);

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

procedure TBrickletOneWire.SearchBusLowLevel(out identifierLength: word; out identifierChunkOffset: word; out identifierChunkData: array [0..6] of uint64; out status: byte)

Returns a list of up to 64 identifiers of the connected 1-Wire devices. Each identifier is 64-bit and consists of 8-bit family code, 48-bit ID and 8-bit CRC.

To get these identifiers the Bricklet runs the SEARCH ROM algorithm, as defined by Maxim.

The following constants are available for this function:

  • BRICKLET_ONE_WIRE_STATUS_OK = 0
  • BRICKLET_ONE_WIRE_STATUS_BUSY = 1
  • BRICKLET_ONE_WIRE_STATUS_NO_PRESENCE = 2
  • BRICKLET_ONE_WIRE_STATUS_TIMEOUT = 3
  • BRICKLET_ONE_WIRE_STATUS_ERROR = 4
function TBrickletOneWire.ResetBus: byte

Resets the bus with the 1-Wire reset operation.

The following constants are available for this function:

  • BRICKLET_ONE_WIRE_STATUS_OK = 0
  • BRICKLET_ONE_WIRE_STATUS_BUSY = 1
  • BRICKLET_ONE_WIRE_STATUS_NO_PRESENCE = 2
  • BRICKLET_ONE_WIRE_STATUS_TIMEOUT = 3
  • BRICKLET_ONE_WIRE_STATUS_ERROR = 4
function TBrickletOneWire.Write(const data: byte): byte

Writes a byte of data to the 1-Wire bus.

The following constants are available for this function:

  • BRICKLET_ONE_WIRE_STATUS_OK = 0
  • BRICKLET_ONE_WIRE_STATUS_BUSY = 1
  • BRICKLET_ONE_WIRE_STATUS_NO_PRESENCE = 2
  • BRICKLET_ONE_WIRE_STATUS_TIMEOUT = 3
  • BRICKLET_ONE_WIRE_STATUS_ERROR = 4
procedure TBrickletOneWire.Read(out data: byte; out status: byte)

Reads a byte of data from the 1-Wire bus.

The following constants are available for this function:

  • BRICKLET_ONE_WIRE_STATUS_OK = 0
  • BRICKLET_ONE_WIRE_STATUS_BUSY = 1
  • BRICKLET_ONE_WIRE_STATUS_NO_PRESENCE = 2
  • BRICKLET_ONE_WIRE_STATUS_TIMEOUT = 3
  • BRICKLET_ONE_WIRE_STATUS_ERROR = 4
function TBrickletOneWire.WriteCommand(const identifier: uint64; const command: byte): byte

Writes a command to the 1-Wire device with the given identifier. You can obtain the identifier by calling SearchBus. The MATCH ROM operation is used to write the command.

If you only have one device connected or want to broadcast to all devices you can set the identifier to 0. In this case the SKIP ROM operation is used to write the command.

The following constants are available for this function:

  • BRICKLET_ONE_WIRE_STATUS_OK = 0
  • BRICKLET_ONE_WIRE_STATUS_BUSY = 1
  • BRICKLET_ONE_WIRE_STATUS_NO_PRESENCE = 2
  • BRICKLET_ONE_WIRE_STATUS_TIMEOUT = 3
  • BRICKLET_ONE_WIRE_STATUS_ERROR = 4

Advanced Functions

procedure TBrickletOneWire.SetCommunicationLEDConfig(const config: byte)

Sets the communication LED configuration. By default the LED shows 1-wire communication traffic by flickering.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is off.

The following constants are available for this function:

  • BRICKLET_ONE_WIRE_COMMUNICATION_LED_CONFIG_OFF = 0
  • BRICKLET_ONE_WIRE_COMMUNICATION_LED_CONFIG_ON = 1
  • BRICKLET_ONE_WIRE_COMMUNICATION_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BRICKLET_ONE_WIRE_COMMUNICATION_LED_CONFIG_SHOW_COMMUNICATION = 3
function TBrickletOneWire.GetCommunicationLEDConfig: byte

Returns the configuration as set by SetCommunicationLEDConfig

The following constants are available for this function:

  • BRICKLET_ONE_WIRE_COMMUNICATION_LED_CONFIG_OFF = 0
  • BRICKLET_ONE_WIRE_COMMUNICATION_LED_CONFIG_ON = 1
  • BRICKLET_ONE_WIRE_COMMUNICATION_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BRICKLET_ONE_WIRE_COMMUNICATION_LED_CONFIG_SHOW_COMMUNICATION = 3
function TBrickletOneWire.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 TBrickletOneWire.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 TBrickletOneWire.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_ONE_WIRE_FUNCTION_SET_COMMUNICATION_LED_CONFIG = 6
  • BRICKLET_ONE_WIRE_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BRICKLET_ONE_WIRE_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BRICKLET_ONE_WIRE_FUNCTION_RESET = 243
  • BRICKLET_ONE_WIRE_FUNCTION_WRITE_UID = 248
procedure TBrickletOneWire.SetResponseExpectedAll(const responseExpected: boolean)

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

procedure TBrickletOneWire.GetSPITFPErrorCount(out errorCountAckChecksum: longword; out errorCountMessageChecksum: longword; out errorCountFrame: longword; out errorCountOverflow: longword)

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.

function TBrickletOneWire.SetBootloaderMode(const mode: byte): byte

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:

  • BRICKLET_ONE_WIRE_BOOTLOADER_MODE_BOOTLOADER = 0
  • BRICKLET_ONE_WIRE_BOOTLOADER_MODE_FIRMWARE = 1
  • BRICKLET_ONE_WIRE_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BRICKLET_ONE_WIRE_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BRICKLET_ONE_WIRE_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BRICKLET_ONE_WIRE_BOOTLOADER_STATUS_OK = 0
  • BRICKLET_ONE_WIRE_BOOTLOADER_STATUS_INVALID_MODE = 1
  • BRICKLET_ONE_WIRE_BOOTLOADER_STATUS_NO_CHANGE = 2
  • BRICKLET_ONE_WIRE_BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BRICKLET_ONE_WIRE_BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BRICKLET_ONE_WIRE_BOOTLOADER_STATUS_CRC_MISMATCH = 5
function TBrickletOneWire.GetBootloaderMode: byte

Returns the current bootloader mode, see SetBootloaderMode.

The following constants are available for this function:

  • BRICKLET_ONE_WIRE_BOOTLOADER_MODE_BOOTLOADER = 0
  • BRICKLET_ONE_WIRE_BOOTLOADER_MODE_FIRMWARE = 1
  • BRICKLET_ONE_WIRE_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BRICKLET_ONE_WIRE_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BRICKLET_ONE_WIRE_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
procedure TBrickletOneWire.SetWriteFirmwarePointer(const pointer: longword)

Sets the firmware pointer for 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.

function TBrickletOneWire.WriteFirmware(const data: array [0..63] of byte): byte

Writes 64 Bytes of firmware at the position as written by 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.

procedure TBrickletOneWire.SetStatusLEDConfig(const config: byte)

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:

  • BRICKLET_ONE_WIRE_STATUS_LED_CONFIG_OFF = 0
  • BRICKLET_ONE_WIRE_STATUS_LED_CONFIG_ON = 1
  • BRICKLET_ONE_WIRE_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BRICKLET_ONE_WIRE_STATUS_LED_CONFIG_SHOW_STATUS = 3
function TBrickletOneWire.GetStatusLEDConfig: byte

Returns the configuration as set by SetStatusLEDConfig

The following constants are available for this function:

  • BRICKLET_ONE_WIRE_STATUS_LED_CONFIG_OFF = 0
  • BRICKLET_ONE_WIRE_STATUS_LED_CONFIG_ON = 1
  • BRICKLET_ONE_WIRE_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BRICKLET_ONE_WIRE_STATUS_LED_CONFIG_SHOW_STATUS = 3
function TBrickletOneWire.GetChipTemperature: smallint

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.

procedure TBrickletOneWire.Reset

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!

procedure TBrickletOneWire.WriteUID(const uid: longword)

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.

function TBrickletOneWire.ReadUID: longword

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

procedure TBrickletOneWire.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.

Constants

const BRICKLET_ONE_WIRE_DEVICE_IDENTIFIER

This constant is used to identify a One Wire 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_ONE_WIRE_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a One Wire Bricklet.