Modbus - OLED 128x64 Bricklet 2.0

This is the description of the Modbus protocol for the OLED 128x64 Bricklet 2.0. General information and technical specifications for the OLED 128x64 Bricklet 2.0 are summarized in its hardware description.

API

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

Basic Functions

BrickletOLED128x64V2.write_pixels_low_level
Function ID:
  • 1
Request:
  • x_start – Type: uint8, Range: [0 to 127]
  • y_start – Type: uint8, Range: [0 to 63]
  • x_end – Type: uint8, Range: [0 to 127]
  • y_end – Type: uint8, Range: [0 to 63]
  • pixels_length – Type: uint16, Range: [0 to 213]
  • pixels_chunk_offset – Type: uint16, Range: [0 to 216 - 1]
  • pixels_chunk_data – Type: bool[448]
Response:
  • no response

Writes pixels to the specified window.

The pixels are written into the window line by line top to bottom and each line is written from left to right.

If automatic draw is enabled (default) the pixels are directly written to the screen. Only pixels that have actually changed are updated on the screen, the rest stays the same.

If automatic draw is disabled the pixels are written to an internal buffer and the buffer is transferred to the display only after draw_buffered_frame is called. This can be used to avoid flicker when drawing a complex frame in multiple steps.

Automatic draw can be configured with the set_display_configuration function.

BrickletOLED128x64V2.read_pixels_low_level
Function ID:
  • 2
Request:
  • x_start – Type: uint8, Range: [0 to 127]
  • y_start – Type: uint8, Range: [0 to 63]
  • x_end – Type: uint8, Range: [0 to 127]
  • y_end – Type: uint8, Range: [0 to 63]
Response:
  • pixels_length – Type: uint16, Range: [0 to 213]
  • pixels_chunk_offset – Type: uint16, Range: [0 to 216 - 1]
  • pixels_chunk_data – Type: bool[480]

Reads pixels from the specified window.

The pixels are read from the window line by line top to bottom and each line is read from left to right.

If automatic draw is enabled (default) the pixels that are read are always the same that are shown on the display.

If automatic draw is disabled the pixels are read from the internal buffer (see draw_buffered_frame).

Automatic draw can be configured with the set_display_configuration function.

BrickletOLED128x64V2.clear_display
Function ID:
  • 3
Request:
  • empty payload
Response:
  • no response

Clears the complete content of the display.

If automatic draw is enabled (default) the pixels are directly cleared.

If automatic draw is disabled the the internal buffer is cleared and the buffer is transferred to the display only after draw_buffered_frame is called. This can be used to avoid flicker when drawing a complex frame in multiple steps.

Automatic draw can be configured with the set_display_configuration function.

BrickletOLED128x64V2.write_line
Function ID:
  • 6
Request:
  • line – Type: uint8, Range: [0 to 7]
  • position – Type: uint8, Range: [0 to 21]
  • text – Type: char[22]
Response:
  • no response

Writes text to a specific line with a specific position. The text can have a maximum of 22 characters.

For example: (1, 10, "Hello") will write Hello in the middle of the second line of the display.

The display uses a special 5x7 pixel charset. You can view the characters of the charset in Brick Viewer.

If automatic draw is enabled (default) the text is directly written to the screen. Only pixels that have actually changed are updated on the screen, the rest stays the same.

If automatic draw is disabled the text is written to an internal buffer and the buffer is transferred to the display only after draw_buffered_frame is called. This can be used to avoid flicker when drawing a complex frame in multiple steps.

Automatic draw can be configured with the set_display_configuration function.

The font conforms to code page 437.

BrickletOLED128x64V2.draw_buffered_frame
Function ID:
  • 7
Request:
  • force_complete_redraw – Type: bool
Response:
  • no response

Draws the currently buffered frame. Normally each call of write_pixels_low_level and write_line draws directly onto the display. If you turn automatic draw off (set_display_configuration), the data is written in an internal buffer and only transferred to the display by calling this function. This can be used to avoid flicker when drawing a complex frame in multiple steps.

Set the force complete redraw to true to redraw the whole display instead of only the changed parts. Normally it should not be necessary to set this to true. It may only become necessary in case of stuck pixels because of errors.

Advanced Functions

BrickletOLED128x64V2.set_display_configuration
Function ID:
  • 4
Request:
  • contrast – Type: uint8, Range: [0 to 255], Default: 143
  • invert – Type: bool, Default: false
  • automatic_draw – Type: bool, Default: true
Response:
  • no response

Sets the configuration of the display.

You can set a contrast value from 0 to 255 and you can invert the color (white/black) of the display.

If automatic draw is set to true, the display is automatically updated with every call of write_pixels_low_level or write_line. If it is set to false, the changes are written into an internal buffer and only shown on the display after a call of draw_buffered_frame.

BrickletOLED128x64V2.get_display_configuration
Function ID:
  • 5
Request:
  • empty payload
Response:
  • contrast – Type: uint8, Range: [0 to 255], Default: 143
  • invert – Type: bool, Default: false
  • automatic_draw – Type: bool, Default: true

Returns the configuration as set by set_display_configuration.

BrickletOLED128x64V2.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.

BrickletOLED128x64V2.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
BrickletOLED128x64V2.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
BrickletOLED128x64V2.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.

BrickletOLED128x64V2.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!

BrickletOLED128x64V2.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.

BrickletOLED128x64V2.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
BrickletOLED128x64V2.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
BrickletOLED128x64V2.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.

BrickletOLED128x64V2.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.

BrickletOLED128x64V2.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.

BrickletOLED128x64V2.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.