Specifications / Modbus Protocol / API / Bricklets / One Wire Bricklet

Modbus - One Wire Bricklet¶

This is the description of the Modbus protocol for the One Wire Bricklet. General information and technical specifications for the One Wire Bricklet are summarized in its hardware description.

API¶

A general description of the Modbus protocol structure can be found here.

Basic Functions¶

BrickletOneWire.search_bus_low_level¶

Function ID:	1
Request:	empty payload
Response:	identifier_length – Type: uint16, Range: [0 to 64] identifier_chunk_offset – Type: uint16, Range: [0 to 2¹⁶ - 1] identifier_chunk_data – Type: uint64[7], Range: [0 to 2⁶⁴ - 1] status – Type: uint8, Range: See meanings

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 meanings are defined for the elements of this function:

For status:

0 = OK
1 = Busy
2 = No Presence
3 = Timeout
4 = Error

BrickletOneWire.reset_bus¶

Function ID:	2
Request:	empty payload
Response:	status – Type: uint8, Range: See meanings

Resets the bus with the 1-Wire reset operation.

The following meanings are defined for the elements of this function:

For status:

0 = OK
1 = Busy
2 = No Presence
3 = Timeout
4 = Error

BrickletOneWire.write¶

Function ID:	3
Request:	data – Type: uint8, Range: [0 to 255]
Response:	status – Type: uint8, Range: See meanings

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

The following meanings are defined for the elements of this function:

For status:

0 = OK
1 = Busy
2 = No Presence
3 = Timeout
4 = Error

BrickletOneWire.read¶

Function ID:	4
Request:	empty payload
Response:	data – Type: uint8, Range: [0 to 255] status – Type: uint8, Range: See meanings

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

The following meanings are defined for the elements of this function:

For status:

0 = OK
1 = Busy
2 = No Presence
3 = Timeout
4 = Error

BrickletOneWire.write_command¶

Function ID:	5
Request:	identifier – Type: uint64, Range: [0 to 2⁶⁴ - 1] command – Type: uint8, Range: [0 to 255]
Response:	status – Type: uint8, Range: See meanings

Writes a command to the 1-Wire device with the given identifier. You can obtain the identifier by calling search_bus_low_level. 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 meanings are defined for the elements of this function:

For status:

0 = OK
1 = Busy
2 = No Presence
3 = Timeout
4 = Error

Advanced Functions¶

BrickletOneWire.set_communication_led_config¶

Function ID:	6
Request:	config – Type: uint8, Range: See meanings, Default: 3
Response:	no response

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 meanings are defined for the elements of this function:

For config:

0 = Off
1 = On
2 = Show Heartbeat
3 = Show Communication

BrickletOneWire.get_communication_led_config¶

Function ID:	7
Request:	empty payload
Response:	config – Type: uint8, Range: See meanings, Default: 3

Returns the configuration as set by set_communication_led_config

The following meanings are defined for the elements of this function:

For config:

0 = Off
1 = On
2 = Show Heartbeat
3 = Show Communication

BrickletOneWire.get_spitfp_error_count¶

Function ID:	234
Request:	empty payload
Response:	error_count_ack_checksum – Type: uint32, Range: [0 to 2³² - 1] error_count_message_checksum – Type: uint32, Range: [0 to 2³² - 1] error_count_frame – Type: uint32, Range: [0 to 2³² - 1] error_count_overflow – Type: uint32, Range: [0 to 2³² - 1]

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.

BrickletOneWire.set_status_led_config¶

Function ID:	239
Request:	config – Type: uint8, Range: See meanings, Default: 3
Response:	no response

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 meanings are defined for the elements of this function:

For config:

0 = Off
1 = On
2 = Show Heartbeat
3 = Show Status

BrickletOneWire.get_status_led_config¶

Function ID:	240
Request:	empty payload
Response:	config – Type: uint8, Range: See meanings, Default: 3

Returns the configuration as set by set_status_led_config

The following meanings are defined for the elements of this function:

For config:

0 = Off
1 = On
2 = Show Heartbeat
3 = Show Status

BrickletOneWire.get_chip_temperature¶

Function ID:	242
Request:	empty payload
Response:	temperature – Type: int16, Unit: 1 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

Returns the temperature 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.

BrickletOneWire.reset¶

Function ID:	243
Request:	empty payload
Response:	no response

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!

BrickletOneWire.get_identity¶

Function ID:	255
Request:	empty payload
Response:	uid – Type: char[8] connected_uid – Type: char[8] position – Type: char, Range: ['a' to 'h', 'z'] hardware_version – Type: uint8[3] 0: major – Type: uint8, Range: [0 to 255] 1: minor – Type: uint8, Range: [0 to 255] 2: revision – Type: uint8, Range: [0 to 255] firmware_version – Type: uint8[3] 0: major – Type: uint8, Range: [0 to 255] 1: minor – Type: uint8, Range: [0 to 255] 2: revision – Type: uint8, Range: [0 to 255] device_identifier – Type: uint16, Range: [0 to 2¹⁶ - 1]

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). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

The device identifier numbers can be found here.

Internal Functions¶

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

BrickletOneWire.set_bootloader_mode¶

Function ID:	235
Request:	mode – Type: uint8, Range: See meanings
Response:	status – Type: uint8, Range: See meanings

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 meanings are defined for the elements of this function:

For mode:

0 = Bootloader
1 = Firmware
2 = Bootloader Wait For Reboot
3 = Firmware Wait For Reboot
4 = Firmware Wait For Erase And Reboot

For status:

0 = OK
1 = Invalid Mode
2 = No Change
3 = Entry Function Not Present
4 = Device Identifier Incorrect
5 = CRC Mismatch

BrickletOneWire.get_bootloader_mode¶

Function ID:	236
Request:	empty payload
Response:	mode – Type: uint8, Range: See meanings

Returns the current bootloader mode, see set_bootloader_mode.

The following meanings are defined for the elements of this function:

For mode:

0 = Bootloader
1 = Firmware
2 = Bootloader Wait For Reboot
3 = Firmware Wait For Reboot
4 = Firmware Wait For Erase And Reboot

BrickletOneWire.set_write_firmware_pointer¶

Function ID:	237
Request:	pointer – Type: uint32, Unit: 1 B, Range: [0 to 2³² - 1]
Response:	no response

Sets the firmware pointer for write_firmware. 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.

BrickletOneWire.write_firmware¶

Function ID:	238
Request:	data – Type: uint8[64], Range: [0 to 255]
Response:	status – Type: uint8, Range: [0 to 255]

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

BrickletOneWire.write_uid¶

Function ID:	248
Request:	uid – Type: uint32, Range: [0 to 2³² - 1]
Response:	no response

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.

BrickletOneWire.read_uid¶

Function ID:	249
Request:	empty payload
Response:	uid – Type: uint32, Range: [0 to 2³² - 1]

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