Ruby - OLED 128x64 Bricklet 2.0

This is the description of the Ruby API bindings 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.

An installation guide for the Ruby API bindings is part of their general description.

Examples

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

Hello World

Download (example_hello_world.rb)

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#!/usr/bin/env ruby
# -*- ruby encoding: utf-8 -*-

require 'tinkerforge/ip_connection'
require 'tinkerforge/bricklet_oled_128x64_v2'

include Tinkerforge

HOST = 'localhost'
PORT = 4223
UID = 'XYZ' # Change XYZ to the UID of your OLED 128x64 Bricklet 2.0

ipcon = IPConnection.new # Create IP connection
oled = BrickletOLED128x64V2.new UID, ipcon # Create device object

ipcon.connect HOST, PORT # Connect to brickd
# Don't use device before ipcon is connected

# Clear display
oled.clear_display

# Write "Hello World" starting from upper left corner of the screen
oled.write_line 0, 0, 'Hello World'

puts 'Press key to exit'
$stdin.gets
ipcon.disconnect

Pixel Matrix

Download (example_pixel_matrix.rb)

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#!/usr/bin/env ruby
# -*- ruby encoding: utf-8 -*-

require 'tinkerforge/ip_connection'
require 'tinkerforge/bricklet_oled_128x64_v2'

include Tinkerforge

HOST = 'localhost'
PORT = 4223
UID = 'XYZ' # Change XYZ to the UID of your OLED 128x64 Bricklet 2.0
WIDTH = 128 # Columns
HEIGHT = 64 # Rows

ipcon = IPConnection.new # Create IP connection
oled = BrickletOLED128x64V2.new UID, ipcon # Create device object

ipcon.connect HOST, PORT # Connect to brickd
# Don't use device before ipcon is connected

# Clear display
oled.clear_display

# Draw checkerboard pattern
pixels = []

for row in 0..HEIGHT - 1
  for column in 0..WIDTH - 1
    pixels[row * WIDTH + column] = (row / 8) % 2 == (column / 8) % 2
  end
end

oled.write_pixels 0, 0, WIDTH-1, HEIGHT-1, pixels

puts 'Press key to exit'
$stdin.gets
ipcon.disconnect

Scribble

Download (example_scribble.rb)

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#!/usr/bin/env ruby
# -*- ruby encoding: utf-8 -*-

require 'rgd'
require 'tinkerforge/ip_connection'
require 'tinkerforge/bricklet_oled_128x64_v2'

include Tinkerforge

HOST = 'localhost'
PORT = 4223
UID = 'XYZ' # Change to your UID
WIDTH = 128 # Columns
HEIGHT = 64 # Rows

def draw_image(oled, start_column, start_row, column_count, row_count, image)
  pixels = []

  # Convert image pixels into 8bit pages
  for row in 0..row_count - 1

    for column in 0..column_count - 1
      index = image[column, row]
      rgba = image.rgba index
      pixels[row*column_count + column] = rgba[0] > 0
    end
  end

  oled.write_pixels 0, 0, WIDTH-1, HEIGHT-1, pixels
end

ipcon = IPConnection.new # Create IP connection
oled = BrickletOLED128x64V2.new UID, ipcon # Create device object

ipcon.connect HOST, PORT # Connect to brickd
# Don't use device before ipcon is connected

# Clear display
oled.clear_display

# Draw checkerboard pattern
image = RGD::Image.create WIDTH, HEIGHT
black = image.color_allocate 0, 0, 0
white = image.color_allocate 255, 255, 255
origin_x = WIDTH / 2
origin_y = HEIGHT / 2
length = HEIGHT / 2 - 2
angle = 0

puts 'Press key to exit'

Thread.new do
  $stdin.gets
  exit
end

while true
    radians = Math::PI * angle / 180.0
    x = (origin_x + length * Math.cos(radians)).to_i
    y = (origin_y + length * Math.sin(radians)).to_i

    image.filled_rectangle 0, 0, WIDTH, HEIGHT, black
    image.line origin_x, origin_y, x, y, white

    draw_image oled, 0, 0, WIDTH, HEIGHT, image
    sleep 0.025

    angle += 1
end

API

All methods listed below are thread-safe.

Basic Functions

BrickletOLED128x64V2::new(uid, ipcon) → oled_128x64_v2
Parameters:
  • uid -- str
  • ipcon -- IPConnection

Creates an object with the unique device ID uid:

oled_128x64_v2 = BrickletOLED128x64V2.new 'YOUR_DEVICE_UID', ipcon

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

BrickletOLED128x64V2#write_pixels(x_start, y_start, x_end, y_end, pixels) → nil
Parameters:
  • x_start -- int
  • y_start -- int
  • x_end -- int
  • y_end -- int
  • pixels -- [bool, bool, ...]

Writes pixels to the specified window.

The x-axis goes from 0 to 127 and the y-axis from 0 to 63. 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(x_start, y_start, x_end, y_end) → [bool, bool, ...]
Parameters:
  • x_start -- int
  • y_start -- int
  • x_end -- int
  • y_end -- int

Reads pixels from the specified window.

The x-axis goes from 0 to 127 and the y-axis from 0 to 63. 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 → nil

Clears the complete content of the display.

BrickletOLED128x64V2#write_line(line, position, text) → nil
Parameters:
  • line -- int
  • position -- int
  • text -- str

Writes text to a specific line (0 to 7) with a specific position (0 to 21). 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.

BrickletOLED128x64V2#draw_buffered_frame(force_complete_redraw) → nil
Parameters:force_complete_redraw -- bool

Draws the currently buffered frame. Normally each call of #write_pixels 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(contrast, invert, automatic_draw) → nil
Parameters:
  • contrast -- int
  • invert -- bool
  • automatic_draw -- bool

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 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.

The default values are contrast 143, inverting off and automatic draw on.

BrickletOLED128x64V2#get_display_configuration → [int, bool, bool]

Returns the configuration as set by #set_display_configuration.

The returned array has the values contrast, invert and automatic_draw.

BrickletOLED128x64V2#get_api_version → [int, int, int]

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.

BrickletOLED128x64V2#get_response_expected(function_id) → bool
Parameters:function_id -- int

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 #set_response_expected. 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 #set_response_expected for the list of function ID constants available for this function.

BrickletOLED128x64V2#set_response_expected(function_id, response_expected) → nil
Parameters:
  • function_id -- int
  • response_expected -- bool

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:

  • BrickletOLED128x64V2::FUNCTION_WRITE_PIXELS = 1
  • BrickletOLED128x64V2::FUNCTION_CLEAR_DISPLAY = 3
  • BrickletOLED128x64V2::FUNCTION_SET_DISPLAY_CONFIGURATION = 4
  • BrickletOLED128x64V2::FUNCTION_WRITE_LINE = 6
  • BrickletOLED128x64V2::FUNCTION_DRAW_BUFFERED_FRAME = 7
  • BrickletOLED128x64V2::FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletOLED128x64V2::FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletOLED128x64V2::FUNCTION_RESET = 243
  • BrickletOLED128x64V2::FUNCTION_WRITE_UID = 248
BrickletOLED128x64V2#set_response_expected_all(response_expected) → nil
Parameters:response_expected -- bool

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

BrickletOLED128x64V2#get_spitfp_error_count → [int, int, int, int]

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.

The returned array has the values error_count_ack_checksum, error_count_message_checksum, error_count_frame and error_count_overflow.

BrickletOLED128x64V2#set_bootloader_mode(mode) → int
Parameters:mode -- int

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:

  • BrickletOLED128x64V2::BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletOLED128x64V2::BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletOLED128x64V2::BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletOLED128x64V2::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletOLED128x64V2::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletOLED128x64V2::BOOTLOADER_STATUS_OK = 0
  • BrickletOLED128x64V2::BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletOLED128x64V2::BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletOLED128x64V2::BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletOLED128x64V2::BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletOLED128x64V2::BOOTLOADER_STATUS_CRC_MISMATCH = 5
BrickletOLED128x64V2#get_bootloader_mode → int

Returns the current bootloader mode, see #set_bootloader_mode.

The following constants are available for this function:

  • BrickletOLED128x64V2::BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletOLED128x64V2::BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletOLED128x64V2::BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletOLED128x64V2::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletOLED128x64V2::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
BrickletOLED128x64V2#set_write_firmware_pointer(pointer) → nil
Parameters:pointer -- int

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(data) → int
Parameters:data -- [int, int, ..61x.., int]

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#set_status_led_config(config) → nil
Parameters:config -- int

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:

  • BrickletOLED128x64V2::STATUS_LED_CONFIG_OFF = 0
  • BrickletOLED128x64V2::STATUS_LED_CONFIG_ON = 1
  • BrickletOLED128x64V2::STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletOLED128x64V2::STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletOLED128x64V2#get_status_led_config → int

Returns the configuration as set by #set_status_led_config

The following constants are available for this function:

  • BrickletOLED128x64V2::STATUS_LED_CONFIG_OFF = 0
  • BrickletOLED128x64V2::STATUS_LED_CONFIG_ON = 1
  • BrickletOLED128x64V2::STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletOLED128x64V2::STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletOLED128x64V2#get_chip_temperature → int

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.

BrickletOLED128x64V2#reset → nil

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#write_uid(uid) → nil
Parameters:uid -- int

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 → int

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

BrickletOLED128x64V2#get_identity → [str, str, str, [int, int, int], [int, int, int], int]

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.

The returned array has the values uid, connected_uid, position, hardware_version, firmware_version and device_identifier.

Constants

BrickletOLED128x64V2::DEVICE_IDENTIFIER

This constant is used to identify a OLED 128x64 Bricklet 2.0.

The #get_identity() function and the ::CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

BrickletOLED128x64V2::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a OLED 128x64 Bricklet 2.0.