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 -- uint16
  • identifier_chunk_offset -- uint16
  • identifier_chunk_data -- uint64[7]
  • status -- uint8

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 parameters of this function:

  • 0: ok, for status
  • 1: busy, for status
  • 2: no presence, for status
  • 3: timeout, for status
  • 4: error, for status
BrickletOneWire.reset_bus
Function ID:

2

Request:

empty payload

Response:
  • status -- uint8

Resets the bus with the 1-Wire reset operation.

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

  • 0: ok, for status
  • 1: busy, for status
  • 2: no presence, for status
  • 3: timeout, for status
  • 4: error, for status
BrickletOneWire.write
Function ID:

3

Request:
  • data -- uint8
Response:
  • status -- uint8

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

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

  • 0: ok, for status
  • 1: busy, for status
  • 2: no presence, for status
  • 3: timeout, for status
  • 4: error, for status
BrickletOneWire.read
Function ID:

4

Request:

empty payload

Response:
  • data -- uint8
  • status -- uint8

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

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

  • 0: ok, for status
  • 1: busy, for status
  • 2: no presence, for status
  • 3: timeout, for status
  • 4: error, for status
BrickletOneWire.write_command
Function ID:

5

Request:
  • identifier -- uint64
  • command -- uint8
Response:
  • status -- uint8

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 parameters of this function:

  • 0: ok, for status
  • 1: busy, for status
  • 2: no presence, for status
  • 3: timeout, for status
  • 4: error, for status

Advanced Functions

BrickletOneWire.set_communication_led_config
Function ID:

6

Request:
  • config -- uint8
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 parameters of this function:

  • 0: off, for config
  • 1: on, for config
  • 2: show heartbeat, for config
  • 3: show communication, for config
BrickletOneWire.get_communication_led_config
Function ID:

7

Request:

empty payload

Response:
  • config -- uint8

Returns the configuration as set by set_communication_led_config

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

  • 0: off, for config
  • 1: on, for config
  • 2: show heartbeat, for config
  • 3: show communication, for config
BrickletOneWire.get_spitfp_error_count
Function ID:

234

Request:

empty payload

Response:
  • error_count_ack_checksum -- uint32
  • error_count_message_checksum -- uint32
  • error_count_frame -- uint32
  • error_count_overflow -- uint32

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_bootloader_mode
Function ID:

235

Request:
  • mode -- uint8
Response:
  • status -- uint8

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 parameters of this function:

  • 0: bootloader, for mode
  • 1: firmware, for mode
  • 2: bootloader wait for reboot, for mode
  • 3: firmware wait for reboot, for mode
  • 4: firmware wait for erase and reboot, for mode
  • 0: ok, for status
  • 1: invalid mode, for status
  • 2: no change, for status
  • 3: entry function not present, for status
  • 4: device identifier incorrect, for status
  • 5: crc mismatch, for status
BrickletOneWire.get_bootloader_mode
Function ID:

236

Request:

empty payload

Response:
  • mode -- uint8

Returns the current bootloader mode, see set_bootloader_mode.

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

  • 0: bootloader, for mode
  • 1: firmware, for mode
  • 2: bootloader wait for reboot, for mode
  • 3: firmware wait for reboot, for mode
  • 4: firmware wait for erase and reboot, for mode
BrickletOneWire.set_write_firmware_pointer
Function ID:

237

Request:
  • pointer -- uint32
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 -- uint8[64]
Response:
  • status -- uint8

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.set_status_led_config
Function ID:

239

Request:
  • config -- uint8
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 parameters of this function:

  • 0: off, for config
  • 1: on, for config
  • 2: show heartbeat, for config
  • 3: show status, for config
BrickletOneWire.get_status_led_config
Function ID:

240

Request:

empty payload

Response:
  • config -- uint8

Returns the configuration as set by set_status_led_config

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

  • 0: off, for config
  • 1: on, for config
  • 2: show heartbeat, for config
  • 3: show status, for config
BrickletOneWire.get_chip_temperature
Function ID:

242

Request:

empty payload

Response:
  • temperature -- int16

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.

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.write_uid
Function ID:

248

Request:
  • uid -- uint32
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 -- uint32

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

BrickletOneWire.get_identity
Function ID:

255

Request:

empty payload

Response:
  • uid -- char[8]
  • connected_uid -- char[8]
  • position -- char
  • hardware_version -- uint8[3]
  • firmware_version -- uint8[3]
  • device_identifier -- uint16

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