HPDL1414 Arduino Library

Arduino library for HPDL1414, 14-segment displays.

Functionality

The library consists of the most basic commands for these displays. They have quite limited character range and don't support custom glyphs. Apart from basic functionality, this library provides extra features for text scrolling.

Configuration

You will need 3 arrays. One for data pins, one for address pins and one for write-enable.
First two are of fixed size (7 and 2 respectively). Third one is flexible.
Initialization will look something like this:

const byte dataPins[7] = {/* [D0:D6] */};
const byte addrPins[2] = {/* [A0:A1] */};
const byte wrenPins[] = {/* [L:R] */};

HPDL1414 hpdl(dataPins, addrPins, wrenPins, sizeof(wrenPins));

Connection

Pinout below is used in library examples.

Physical	Name	Arduino Pin
1*	D5	D7
2	D4	D6
3	!WE	D11
4	A1	D10
5	A0	D9
6	Vcc	5V
7	GND	GND
8	D0	D2
9	D1	D3
10	D2	D4
11	D3	D5
12	D6	D8

Pin 1 is marked with a notch.

Daisychain

1. Connect all pins in parallel except for the !WE pins.
2. Add segment's !WE pin to the code
3. Done

What you will care about the most

You can print everything that Arduino would let you on other displays. For basic use you won't need more than these:

hpdl.print()
hpdl.clear()
hpdl.setCursor(byte pos)

Scrolling

This release of HPDL1414 library includes text scrolling via HPDL1414Scroll.h.
To use new features just create HPDL1414Scroll object. Everything is printed to a buffer, so don't forget to call display().
Scrolling moves the entire buffer in both ways. This means characters can "disappear" from both sides.
Default buffer size is equal to the display. That means if you have 2 displays the buffer is 8 bytes, if you have 3 it's 12 etc.
You can provide external buffer with begin(char* bufptr, byte size). When in doubt, just use default begin().
Note that printOverflow() doesn't make sense when you use default text buffer. You should use printBufferOverflow() instead.

Buffer access

Since buffer is stored as C-style char array it might be unnecessary to use C++-style string operators.
To get char at selected position you can use normal array operators i.e. hpdl[1]. You must provide a valid character or use translate(char).

Examples

Base library is very simple and straightforward. You want something printed - you got it.
Scrolling however needs some explaination.

HPDL1414.h

SegmentTest - Test one/more segments. Every segment will be counted
OverflowExample - Printing overflowing characters at the beginning of the display

HPDL1414Scroll.h

ScrollExample - Scrolling text from left to right
ScrollBufferExample - Manipulating buffer contents
ScrollPong - Word floating left-right
ScrollAdvancedBuffer - Manipulating both buffer and printing positions
ScrollBufferOverflow - Printing overflowing characters at the beginning of the display
ScrollCustomBuffer - Using custom text buffer for greater flexibility

Limitations

These displays work on limited set of characters (ASCII 32-95). Library has built-in "translator" for lowercase letters.
You can disable character validation by defining NO_ASCII_TRANSLATION before include, or uncommenting it in HPDL1414.h directly.

TODO

Recode assignments to use translate as little as possible, including operator.
String validation/automatic translation is also an option. Possibly return current buffer contents.

Does it work?

HPDL1414 Datasheet

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