This is the description of the Shell API bindings for the LCD 16x2 Bricklet. General information and technical specifications for the LCD 16x2 Bricklet are summarized in its hardware description.
An installation guide for the Shell API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
Download (example-hello-world.sh)
1 2 3 4 5 6 7 8 9 10 | #!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this
uid=XYZ # Change XYZ to the UID of your LCD 16x2 Bricklet
# Turn backlight on
tinkerforge call lcd-16x2-bricklet $uid backlight-on
# Write "Hello World"
tinkerforge call lcd-16x2-bricklet $uid write-line 0 0 "Hello World"
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Download (example-button-callback.sh)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | #!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this
uid=XYZ # Change XYZ to the UID of your LCD 16x2 Bricklet
# Handle incoming button pressed callbacks
tinkerforge dispatch lcd-16x2-bricklet $uid button-pressed &
# Handle incoming button released callbacks
tinkerforge dispatch lcd-16x2-bricklet $uid button-released &
echo "Press key to exit"; read dummy
kill -- -$$ # Stop callback dispatch in background
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | #!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this
uid=XYZ # Change XYZ to the UID of your LCD 16x2 Bricklet
# Turn backlight on
tinkerforge call lcd-16x2-bricklet $uid backlight-on
# Write a string using sed to map to the LCD charset
# Note: This assumes that the shell supports UTF-8
tinkerforge call lcd-16x2-bricklet $uid write-line 0 0\
"`echo 'Stromstärke: 5µA' | sed 'y/\o134~¥→←°αÄäßεµςρ√¹¤¢ⱠñÖöϴ∞ΩÜüΣπ÷■/\o244\o55\o134\o176\o177\o337\o340\o341\o341\o342\o343\o344\o345\o346\o350\o351\o353\o354\o355\o356\o357\o357\o362\o363\o364\o365\o365\o366\o367\o375\o377/'`"
# Write a string directly including characters from the LCD charset
tinkerforge call lcd-16x2-bricklet $uid write-line 1 0\
"`printf 'Drehzahl: 1000s\xe9'`"
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Possible exit codes for all tinkerforge commands are:
The common options of the call and dispatch commands are documented here. The specific command structure is shown below.
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The call command is used to call a function of the LCD 16x2 Bricklet. It can take several options:
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The dispatch command is used to dispatch a callback of the LCD 16x2 Bricklet. It can take several options:
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The <function> to be called can take different options depending of its kind. All functions can take the following options:
Getter functions can take the following options:
Setter functions can take the following options:
The --expect-response option for setter functions allows to detect timeouts and other error conditions calls of setters as well. The device will then send a response for this purpose. If this option is not given for a setter function then no response is send and errors are silently ignored, because they cannot be detected.
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The <callback> to be dispatched can take several options:
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Writes text to a specific line with a specific position. The text can have a maximum of 16 characters.
For example: (0, 5, "Hello") will write Hello in the middle of the first line of the display.
The display uses a special charset that includes all ASCII characters except backslash and tilde. The LCD charset also includes several other non-ASCII characters, see the charset specification for details. The Unicode example above shows how to specify non-ASCII characters and how to translate from Unicode to the LCD charset.
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Deletes all characters from the display.
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Turns the backlight on.
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Turns the backlight off.
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Returns true if the backlight is on and false otherwise.
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Configures if the cursor (shown as "_") should be visible and if it should be blinking (shown as a blinking block). The cursor position is one character behind the the last text written with write-line.
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Returns the configuration as set by set-config.
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Returns true if the button is pressed.
If you want to react on button presses and releases it is recommended to use the button-pressed and button-released callbacks.
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The LCD 16x2 Bricklet can store up to 8 custom characters. The characters consist of 5x8 pixels and can be addressed with the index 0-7. To describe the pixels, the first 5 bits of 8 bytes are used. For example, to make a custom character "H", you should transfer the following:
The characters can later be written with write-line by using the characters with the byte representation 8 to 15.
You can play around with the custom characters in Brick Viewer since version 2.0.1.
Custom characters are stored by the LCD in RAM, so they have to be set after each startup.
New in version 2.0.1 (Plugin).
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Returns the custom character for a given index, as set with set-custom-character.
New in version 2.0.1 (Plugin).
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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). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.
The device identifier numbers can be found here.
Callbacks can be used to receive time critical or recurring data from the device:
tinkerforge dispatch lcd-16x2-bricklet <uid> example
The available callbacks are described below.
Note
Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.
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This callback is triggered when a button is pressed. The parameter is the number of the button.
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This callback is triggered when a button is released. The parameter is the number of the button.