1357 lines
34 KiB
Plaintext
1357 lines
34 KiB
Plaintext
<sect1 id="hd44780-howto">
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<title>The HD44780 Driver</title>
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<para>
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There are several ways of wiring up the HD44780 devices. Your choice
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will probably be governed largely by your ability to wire up each one
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and/or a desire to use the device with other programs.
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</para>
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<para>
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The LCDproc HD44780 driver supports the following connections on a
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parallel port:
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</para>
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<itemizedlist>
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<listitem><para>4-bit</para></listitem>
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<listitem><para>8-bit (winamp style)</para></listitem>
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<listitem><para>extended 8-bit (LCD + LED bargraph)</para></listitem>
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<listitem><para>serial LPT</para></listitem>
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</itemizedlist>
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<para>
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And supports a PIC-an-LCD or LCD serializer connected to a serial port.
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</para>
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<para>
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The driver also lets you use multiple displays as a single virtual
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display. For example, a 4, 2 and 1 line display can be used to form a
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7 line display. The number of displays is limited by the individual
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HD44780 driver.
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</para>
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<sect2 id="hd44780-connections">
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<title>Connections</title>
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<sect3 id="hd44780-connections-common">
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<title>Common connections for all connectiontypes</title>
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<para>
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No matter what connectiontype you choose, you will always need some
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connections. They are explaned here.
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</para>
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<sect4 id="hd44780-connections-power">
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<title>Power</title>
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<para>
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All variants use the same method of obtaining power. i.e., for each LCD:
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</para>
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<table>
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<title>HD44780: Power Connections</title>
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<tgroup cols="3">
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<thead>
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<row>
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<entry>LCD</entry>
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<entry>pin</entry>
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<entry>signal</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>1</entry>
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<entry>GND</entry>
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<entry>(connect to any of pins 18 - 25 of you parallel port)</entry>
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</row>
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<row>
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<entry>2</entry>
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<entry>+5V</entry>
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<entry></entry>
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</row>
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<row>
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<entry>3</entry>
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<entry>Vadj</entry>
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<entry>(contrast)</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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<warning>
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<para>
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Always double check your power connection, your display will probably
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NOT survive a reversely connected supply !
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</para>
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</warning>
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<para>
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There are several ways to get 5V:
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</para>
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<itemizedlist>
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<listitem><para>Connect to a 5V line intented for disk drives (the red
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wire is 5V, black is GND).</para></listitem>
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<listitem><para>Get it from a joystick port (pin 1 and 9 are 5V, 4, 5
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and 12 are GND). It seems that some soundcards can use these lines for
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communication, so if you want to use this first check wether it really
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gives a 'clean' 5V.</para></listitem>
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<listitem><para>If you don't have a backlight, you can sometimes get
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the needed mA's from the LPT port itself. Connect a few diodes from the
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data pins to a capacitor and you have the 5V. If it's strong enough is
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another question...</para></listitem>
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<listitem><para>Get it from the keyboard connector. I do not recommend
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to use this with a backlight, as the keyboard connector is often protected
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with a fuse of 100mA or 200mA.</para></listitem>
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</itemizedlist>
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<figure>
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<title>HD44780: Connecting the contrast adjusting pin (Vadj.)</title>
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<screen>
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<![CDATA[
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(variable resistor)
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.------.
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Vcc ---| 10k |--- GND
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`---^--'
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/|\
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Vadj.
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]]>
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</screen>
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</figure>
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</sect4>
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<sect4 id="hd44780-connections-keypad">
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<title>Keypad</title>
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<para>
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You can connect a keypad with all connection types. The maximum supported
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number of keys differs per type. There are several ways to connect the keys
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to the input pins.
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</para>
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<sect5 id="hd44780-connections-keypad-direct">
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<title>Direct Keys</title>
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<para>
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If you connect a key like sketched below, then you can only connect one key
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per input pin. It is a simple solution if you need only few keys.
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</para>
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<figure>
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<title>HD44780: Direct Keys</title>
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<screen>
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<![CDATA[
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O 5V
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-
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| | 10k
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-
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+-----------o input (X)
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o
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\
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o
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=== GND
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]]>
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</screen>
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</figure>
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<para>
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By default, the following keystrokes are generated by the different keys:
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</para>
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<table>
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<title>HD44780: Default Keystrokes</title>
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<tgroup cols="2">
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<tbody>
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<row>
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<entry>X0</entry>
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<entry>A</entry>
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</row>
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<row>
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<entry>X1</entry>
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<entry>B</entry>
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</row>
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<row>
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<entry>X2</entry>
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<entry>C</entry>
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</row>
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<row>
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<entry>X3</entry>
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<entry>D</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</sect5>
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<sect5 id="hd44780-connections-keypad-matrix">
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<title>Matrix Keys</title>
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<para>
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Using a matrix, we can connect much more keys. To simplify the drawing here,
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we replace all switches with an @ symbol:
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</para>
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<figure>
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<title>HD44780: Single Matrix Key</title>
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<screen>
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<![CDATA[
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X line
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Y line ---+---------
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o | = --@--
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\ | |
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o |
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+---+
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]]>
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</screen>
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</figure>
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<para>
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We connect the matrix of keys like this:
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</para>
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<figure>
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<title>HD44780: Complete Key Matrix</title>
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<screen>
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<![CDATA[
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Y0 o---|<---@--@--@
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Y1 o---|<---@--@--@
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Y2 o---|<---@--@--@
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Y3 o---|<---@--@--@ O 5V
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diodes | | | ___ |
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1N4148 +----------|___|---+
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| | | ___ |
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| +-------|___|---+
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| | | ___ |
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| | +----|___|---+ resistors 22k
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o o o
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X0 X1 X2
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]]>
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</screen>
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</figure>
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<para>
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As you can see, you need 1 resistor per X line, and 1 diode per Y line.
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Lcdproc will presume that you have a keypad with a layout like a telephone
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connected, with X and Y lines connected as show. To be more precise, it
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assumes this:
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</para>
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<figure>
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<title>HD44780: Keypad Layout</title>
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<screen>
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<![CDATA[
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X0 X1 X2 X3
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Y0 1 2 3 A
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Y1 4 5 6 B
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Y2 7 8 9 C
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Y3 * 0 # D
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]]>
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</screen>
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</figure>
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<para>
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If you only need 10 keys, leave the rest away. However, the lcdproc menu is
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controlled by the keystrokes A to D. You should modify and recompile the
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driver to get an other keypad layout.
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</para>
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<para>
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You can buy arrays of keys that are connected like this in the electronics
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shop. They usually call it a matrix keypad. To hook it to lcdproc, you
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would only need to add the resistors and diodes.
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</para>
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<para>
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If you want to use just one return line, for example with the serialLpt
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wiring, it looks (completely drawn) like this:
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</para>
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<figure>
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<title>HD44780: One Return Line</title>
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<screen>
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<![CDATA[
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O 5V
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.-.
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| | 4k7 or 22k
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diodes | |
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1N4148 '-'
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___ |
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Y0 o---|<---o o---+
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___ |
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Y1 o---|<---o o---+
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___ |
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Y2 o---|<---o o---+
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___ |
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Y3 o---|<---o o---+----o return line
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]]>
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</screen>
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</figure>
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<tip>
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<para>
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If the driver generates keypresses without that you actually press a key,
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it might be that the unconnected input lines are picking up
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electromagnetic waves from the air. In that case connect the unconnected
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input lines (pin 10, 11, 12, 13 and 15 of the LPT) to VCC = 5V.
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</para>
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</tip>
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</sect5>
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</sect4>
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<sect4 id="hd44780-connections-backlight">
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<title>Backlight</title>
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<para>
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A small extension allows you to switch the backlight of the display on
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and off. At the moment only the 4bit and winamp connection types support
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this. The extension uses one output pin, you cannot use that pin for other
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functions anymore. The wiring looks like this:
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</para>
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<figure>
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<title>HD44780: Backlight Wiring</title>
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<screen>
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<![CDATA[
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O 5V
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___ |
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+---|___|---+
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LPT Sub-D connector | 4k7 |
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| |e
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___ | b |/
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BL pin o------------|___|---+---------|
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1k |\
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bc327 |c
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| LCD connector
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+--------o 15 backlight
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+--------o 16 GND backlight
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=== GND
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Note: 4k7 means 4,7 kohm.
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The BC327 transistor has the following connections:
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_____
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|bc327|
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|_____|
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c b e
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]]>
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</screen>
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</figure>
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<caution>
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<para>
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Sometimes the backlight connections are not on the 'main' connector, but on
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the side. If that is the case, there is usually NO RESISTOR present to limit
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the current through the LEDs. Therefor you should then add a resistor after
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the transistor of about 10 ohm (see display documentation).
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</para>
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</caution>
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<tip>
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<para>
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If you want the backlight to light a bit while it's switched 'off', you can
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add a resistor bypassing the transistor from e to c, with a value of, say
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47ohm or 22ohm. (My 4x20 has an internal resistor of 6ohm, so with 47 ohm
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extra it lights at only 1/9th. I like this. Joris.)
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</para>
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</tip>
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</sect4>
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</sect3>
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<sect3 id="hd44780-4-bit">
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<title>4-bit</title>
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<para>
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This is originally based on "lcdtext" (by Matthias Prinke).
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</para>
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<table>
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<title>HD44780: 4-bit Pinouts (1)</title>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>printer port</entry>
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<entry>LCD</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>D0 (2)</entry>
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<entry>D4 (11)</entry>
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</row>
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<row>
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<entry>D1 (3)</entry>
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<entry>D5 (12)</entry>
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</row>
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<row>
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<entry>D2 (4)</entry>
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<entry>D6 (13)</entry>
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</row>
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<row>
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<entry>D3 (5)</entry>
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<entry>D7 (14)</entry>
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</row>
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<row>
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<entry>D4 (6)</entry>
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<entry>RS (4)</entry>
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</row>
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<row>
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<entry>D5 (7)</entry>
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<entry>RW (5) (LCD3 - 6) (optional - pull all LCD RW low (*) )</entry>
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</row>
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<row>
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<entry>D6 (8)</entry>
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<entry>EN (6)</entry>
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</row>
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<row>
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<entry>D7 (9)</entry>
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<entry>EN2 (LCD2 - 6) (optional)</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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<para>
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(*) on the RW line of the display: this line decides whether the display receives data from the
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LPT port, or whether it sends data to the LPT port. If grounded, it receives. If High or connected
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to nothing at all, it "sends" (i.e., will not work as intended). So, if you are not sure that
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you need it otherwise, then connect it to GND. This certainly applies if you have only one display.
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</para>
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<para>
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If you want to connect more than two displays to the parallel port then
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wire D5 (pin 7) to the enable line (pin 6) of the third LCD. Then for
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displays four to seven use:
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</para>
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<table>
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<title>HD44780: 4-bit Pinouts (2)</title>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>printer port</entry>
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<entry>LCD</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>STR (1)</entry>
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<entry>EN4</entry>
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</row>
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<row>
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<entry>LF (14)</entry>
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<entry>EN5</entry>
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</row>
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<row>
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<entry>INIT (16)</entry>
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<entry>EN6</entry>
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</row>
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<row>
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<entry>SEL (17)</entry>
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<entry>EN7</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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<para>
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The optional keypad can be connected as follows:
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</para>
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<table>
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<title>HD44780: 4-bit Keypad Pinouts</title>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>printer port</entry>
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<entry>LCD</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>D0 (2)</entry>
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<entry>Y0</entry>
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</row>
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<row>
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<entry>D1 (3)</entry>
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<entry>Y1</entry>
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</row>
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<row>
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<entry>D2 (4)</entry>
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<entry>Y2</entry>
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</row>
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<row>
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<entry>D3 (5)</entry>
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<entry>Y3</entry>
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</row>
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<row>
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<entry>D4 (6)</entry>
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<entry>Y4</entry>
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</row>
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<row>
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<entry>D5 (7)</entry>
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<entry>Y5</entry>
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</row>
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<row>
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<entry>nSTRB (1)</entry>
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<entry>Y6</entry>
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</row>
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<row>
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<entry>nLF (14)</entry>
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<entry>Y7</entry>
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</row>
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<row>
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<entry>INIT (16)</entry>
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<entry>Y8</entry>
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</row>
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<row>
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<entry>nSEL (17)</entry>
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<entry>Y9</entry>
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</row>
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<row>
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<entry></entry>
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<entry></entry>
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</row>
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<row>
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<entry>nACK (10)</entry>
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<entry>X0</entry>
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</row>
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<row>
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<entry>BUSY (11)</entry>
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<entry>X1</entry>
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</row>
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<row>
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<entry>PAPEREND (12)</entry>
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<entry>X2</entry>
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</row>
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<row>
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<entry>SELIN (13)</entry>
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<entry>X3</entry>
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</row>
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<row>
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<entry>nFAULT (15)</entry>
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<entry>X4</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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<para>
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The optional backlight wiring should be connected to D5, pin 7.
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</para>
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</sect3>
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<sect3 id="hd44780-8-bit-winamp">
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<title>8-bit "Winamp"</title>
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<para>
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This type of connection should work with winamp.
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|
</para>
|
|
|
|
<figure>
|
|
<title>HD44780: "Winamp" wiring</title>
|
|
<screen>
|
|
<![CDATA[
|
|
|
|
printer port LCD
|
|
|
|
D0 (2) D0 (7)
|
|
D1 (3) D1 (8)
|
|
D2 (4) D2 (9)
|
|
D3 (5) D3 (10)
|
|
D4 (6) D4 (11)
|
|
D5 (7) D5 (12)
|
|
D6 (8) D6 (13)
|
|
D7 (9) D7 (14)
|
|
nSTRB (1) EN (6)
|
|
nLF (14) nRW (5) (EN3 6 - LCD 3) (optional (*) )
|
|
INIT (16) RS (4)
|
|
nSEL (17) EN2 (6 - LCD 2) (optional)
|
|
|
|
]]>
|
|
</screen>
|
|
</figure>
|
|
|
|
<para>
|
|
(*) on the RW line of the display: this line decides whether the display receives data from the
|
|
LPT port, or whether it sends data to the LPT port. If grounded, it receives. If High or connected
|
|
to nothing at all, it "sends" (i.e., will not work as intended). So, if you are not sure that
|
|
you need it otherwise, then connect it to GND. This certainly applies if you have only one display.
|
|
</para>
|
|
|
|
<para>
|
|
If you want the display to work with the Winamp plugin, wire nLF (pin 14)
|
|
to nRW of your LCD. You can then use the plugin in bidirectional mode (wich
|
|
is much faster). With 3 connected LCDs this is not possible.
|
|
Note from Benjamin: I haven't tried using winamp while having the third LCD
|
|
connected to this line.
|
|
</para>
|
|
|
|
<para>
|
|
The optional keypad can be connected as follows:
|
|
</para>
|
|
|
|
<figure>
|
|
<title>HD44780: "Winamp" wiring - Keypad</title>
|
|
<screen>
|
|
<![CDATA[
|
|
|
|
printer port keypad
|
|
|
|
D0 (2) Y0
|
|
D1 (3) Y1
|
|
D2 (4) Y2
|
|
D3 (5) Y3
|
|
D4 (6) Y4
|
|
D5 (7) Y5
|
|
D6 (8) Y6
|
|
D7 (9) Y7
|
|
nLF (14) Y8
|
|
INIT (16) Y9
|
|
|
|
nACK (10) X0
|
|
BUSY (11) X1
|
|
PAPEREND (12) X2
|
|
SELIN (13) X3
|
|
nFAULT (15) X4
|
|
|
|
]]>
|
|
</screen>
|
|
</figure>
|
|
|
|
<para>
|
|
The optional backlight wiring should be connected to nSEL, pin 17.
|
|
</para>
|
|
|
|
</sect3>
|
|
|
|
<sect3 id="hd44780-8-bit-lcdtime">
|
|
<title>8-bit "lcdtime"</title>
|
|
|
|
<para>
|
|
This is originally based on "lcdtime" (by Benjamin Tse
|
|
<email>blt@ComPorts.com</email>) and allows you to combine the LCD with a LED
|
|
bargraph. The LCD is driven by LCDproc and the LEDs by another program
|
|
such as portato. Further details can be obtained from:
|
|
</para>
|
|
|
|
<para>
|
|
<ulink url="http://metalab.unc.edu/pub/linux/system/status/lcdtime-0.2.tar.gz">http://metalab.unc.edu/pub/linux/system/status/lcdtime-0.2.tar.gz</ulink>
|
|
<ulink url="http://metalab.unc.edu/pub/linux/system/status/meter-0.2.tar.gz">http://metalab.unc.edu/pub/linux/system/status/meter-0.2.tar.gz</ulink>
|
|
<ulink url="http://metalab.unc.edu/pub/linux/system/status/portato-1.2.tar.gz">http://metalab.unc.edu/pub/linux/system/status/portato-1.2.tar.gz</ulink>
|
|
</para>
|
|
|
|
<note>
|
|
<para>
|
|
Theoretically this wiring sends the data over twice as slow as the
|
|
winamp or ext8bit wirings, because it only sends 4 bits at a time.
|
|
</para>
|
|
</note>
|
|
|
|
<para>
|
|
The LCD connections are:
|
|
</para>
|
|
|
|
<figure>
|
|
<title>HD44780: "lcdtime" wiring</title>
|
|
<screen>
|
|
<![CDATA[
|
|
|
|
printer port LCD
|
|
|
|
D0 (2) D0 (7)
|
|
D1 (3) D1 (8)
|
|
D2 (4) D2 (9)
|
|
D3 (5) D3 (10)
|
|
D4 (6) D4 (11)
|
|
D5 (7) D5 (12)
|
|
D6 (8) D6 (13)
|
|
D7 (9) D7 (14)
|
|
nSEL (17) -
|
|
nSTRB (1) RS (4)
|
|
nLF (14) RW (5) (LCD2 - 6) (optional - pull all LCD RW low (*))
|
|
INIT (16) EN (6)
|
|
|
|
]]>
|
|
</screen>
|
|
</figure>
|
|
|
|
<para>
|
|
(*) on the RW line of the display: this line decides whether the display receives data from the
|
|
LPT port, or whether it sends data to the LPT port. If grounded, it receives. If High or connected
|
|
to nothing at all, it "sends" (i.e., will not work as intended). So, if you are not sure that
|
|
you need it otherwise, then connect it to GND. This certainly applies if you have only one display.
|
|
</para>
|
|
|
|
<para>
|
|
See the lcdtime tar-ball (above) for full details of the bargraph
|
|
connections.
|
|
</para>
|
|
|
|
<para>
|
|
The optional keypad can be connected as follows:
|
|
</para>
|
|
|
|
<figure>
|
|
<title>HD44780: "lcdtime" wiring - keypad</title>
|
|
<screen>
|
|
<![CDATA[
|
|
|
|
printer port keypad
|
|
|
|
D0 (2) Y0
|
|
D1 (3) Y1
|
|
D2 (4) Y2
|
|
D3 (5) Y3
|
|
D4 (6) Y4
|
|
D5 (7) Y5
|
|
D6 (8) Y6
|
|
D7 (9) Y7
|
|
nSTRB (1) Y8
|
|
nSEL (17) Y9
|
|
|
|
nACK (10) X0
|
|
BUSY (11) X1
|
|
PAPEREND (12) X2
|
|
SELIN (13) X3
|
|
nFAULT (15) X4
|
|
|
|
]]>
|
|
</screen>
|
|
</figure>
|
|
|
|
<para>
|
|
The backlight wiring should be attached to nSEL, pin 17. Because the portato
|
|
program (mentioned above) also uses this pin to control the bargraph, you
|
|
cannot use the backlight control together with the bargraph.
|
|
</para>
|
|
|
|
</sect3>
|
|
|
|
<sect3 id="hd44780-seriallpt">
|
|
<title>Serial LPT</title>
|
|
|
|
<para>
|
|
This interface uses a handful of wires to interface to the
|
|
HD44780. Suitable for high noise, long connections. Designed by
|
|
Andrew McMeikan <email>andrewm@engineer.com</email>. The original wiring and
|
|
driver can be found at:
|
|
</para>
|
|
<para>
|
|
<ulink url="http://members.xoom.com/andrewmuck">http://members.xoom.com/andrewmuck</ulink>
|
|
</para>
|
|
|
|
<para>
|
|
I (Joris) have extended this driver and the wiring a bit. It now supports
|
|
keys again (it had earlier supported keys, but some time did not).
|
|
</para>
|
|
|
|
<para>
|
|
Further I have extended the driver and the wiring to be able to run
|
|
using 2 instead of 3 output pins. That's even one less pin ! :)
|
|
</para>
|
|
|
|
<para>
|
|
Of course the use of fewer lines than the other wirings can not stay
|
|
without drawbacks. In this case the simplicity of the long feeding wires
|
|
is compensated by some intelligence in the decoding of the data. If you
|
|
have no experience with the soldering iron, I do not recommend to build
|
|
this wiring.
|
|
</para>
|
|
|
|
<para>
|
|
OK, so here is the wiring. First of the 'simple' 3 wires version. IC1 is
|
|
the shift register, a 4094. Do not forget to connect the 5V to pin 16 and
|
|
GND to pin 8 of the IC.
|
|
</para>
|
|
|
|
<figure>
|
|
<title>HD44780: Serial LPT wiring ('simple')</title>
|
|
<screen>
|
|
<![CDATA[
|
|
|
|
IC1
|
|
-----------
|
|
| 4094 |
|
|
5V | shift reg | display
|
|
O | | keys
|
|
| 1| |4
|
|
+----|STR Q0|--------------------o 11 D4 Y0
|
|
| | |5
|
|
Data | 2| Q1|--------------------o 12 D5 Y1
|
|
D3 5 o-------------------------|D |6
|
|
| | Q2|--------------------o 13 D6 Y2
|
|
| 3| |7
|
|
D4 6 o-------------------------|CK Q3|--------------------o 14 D7 Y3
|
|
| | |14
|
|
| 15| Q4|--------------------o Y4
|
|
+----|OE |13
|
|
| Q5|--------------------o 4 RS Y5
|
|
| |12
|
|
| Q6|--------------------o Y6
|
|
| |11
|
|
| Q7|--------------------o Y7
|
|
| |9
|
|
| QS|-- +--o 5 RW
|
|
| __|10 |
|
|
| QS|-- ===
|
|
| |
|
|
-----------
|
|
|
|
|
|
D2 4 o----------------------------------------------------------o 6 EN
|
|
|
|
D7 9 o----------------------------------------------------------o 6 EN2
|
|
(2nd LCD)
|
|
|
|
|
|
5V O-----+--------+-------------------------------+-----o 2 VCC
|
|
| | |
|
|
| | |
|
|
|100n O 16 .-.
|
|
--- IC1 | |<---o 3 Vlcd
|
|
--- O 8 | |10k
|
|
| | '-'
|
|
GND | | |
|
|
18..25 o-----------+--------+-----------------------+-------+-----o 1 GND
|
|
|
|
|
=== GND
|
|
|
|
]]>
|
|
</screen>
|
|
</figure>
|
|
|
|
<para>
|
|
The second possible wiring is with 2 output lines. This one is a bit more
|
|
complex. If you do not understand the schematic, do not build it.
|
|
</para>
|
|
|
|
<figure>
|
|
<title>HD44780: Serial LPT wiring ('complex')</title>
|
|
<screen>
|
|
<![CDATA[
|
|
|
|
IC2
|
|
-----------
|
|
| 74HCT164 |
|
|
| shift reg | display
|
|
| | keys
|
|
Data 1| |3
|
|
D3 5 o---------------------+---|D Q0|--------------------o 11 D4 Y0
|
|
| | |4
|
|
| 2| Q1|--------------------o 12 D5 Y1
|
|
+---|D |5
|
|
| Q2|--------------------o 13 D6 Y2
|
|
| |6
|
|
| Q3|--------------------o 14 D7 Y3
|
|
| |10
|
|
Clock 8| Q4|--------------------o Y4
|
|
D4 6 o-------------------------|CK |11
|
|
| Q5|--------------------o 4 RS Y5
|
|
___ 9|\ 8 9|_ |12
|
|
+--|___|--+----| >o----|R Q6|--------------------o Y6
|
|
| 22k | |/ | |13
|
|
| --- IC1 | Q7|---+ +--o 5 RW
|
|
| --- | | | 5V |
|
|
| |100p ----------- | O ===
|
|
| | | |
|
|
| === | .-.
|
|
| | | |22k
|
|
+--------------------------------------+ | |
|
|
| '-'
|
|
| ___ 11|\ 10 | 5|\ 6
|
|
+--|___|--+----| >o-------------------||-----+----| >o--o 6 EN
|
|
22k | |/ 22p |/
|
|
--- IC1 IC1
|
|
---
|
|
|22p
|
|
| IC1=74HCT14 (6x Schmitt trigger inverter)
|
|
===
|
|
|
|
|
|
5V O--+-------+------+------+-----------------------+-----o 2 VCC
|
|
| | | | 13|\ 12 |
|
|
| | | +---| >o- |
|
|
|100n O 14 O 14 |/ .-.
|
|
--- IC1 IC2 | |<---o 3 Vlcd
|
|
--- O 7 O 7 1|\ 2 3|\ 4 | |10k
|
|
| | | +--| >o- +--| >o- '-'
|
|
GND | | | | |/ | |/ |
|
|
18..25 o------+-------+------+-------+----------+-----+-----+-----o 1 GND
|
|
|
|
|
=== GND
|
|
|
|
]]>
|
|
</screen>
|
|
</figure>
|
|
|
|
<sect4 id="hd44780-seriallpt-keypad">
|
|
<title>Serial LPT Keypad</title>
|
|
|
|
<note>
|
|
<para>
|
|
To understand this part of the serialLpt documentation, you also need to
|
|
read the <link linkend="hd44780-connections-keypad">keypad section</link> in this document.
|
|
</para>
|
|
</note>
|
|
|
|
<para>
|
|
serialLpt wiring supports a keypad. The 3 wires version supports
|
|
8 keys, or if you use multiple return lines up to 8 x 5 = 40 lines. The
|
|
2 wires version supports 7 keys, or with multiple return lines
|
|
7 x 5 = 35 keys.
|
|
</para>
|
|
|
|
<figure>
|
|
<title>HD44780: Serial LPT - Keypad return lines</title>
|
|
<screen>
|
|
<![CDATA[
|
|
|
|
nACK (10) X0
|
|
BUSY (11) X1
|
|
PAPEREND (12) X2
|
|
SELIN (13) X3
|
|
nFAULT (15) X4
|
|
|
|
]]>
|
|
</screen>
|
|
</figure>
|
|
|
|
<para>
|
|
On lines longer than, say a meter, you should buffer the return line(s).
|
|
If you only have 1 return line, you can buffer it with two remaining
|
|
buffers from the 74HCT14:
|
|
</para>
|
|
|
|
<figure>
|
|
<title>HD44780: Serial LPT - Keypad return lines buffered</title>
|
|
<screen>
|
|
<![CDATA[
|
|
|
|
1|\ 2 13|\ 12 ___
|
|
keypad o-----| >o------| >o---|___|---+---o input pin on LPT port
|
|
return |/ |/ 220E |
|
|
IC1 IC1 ---
|
|
--- 1nF
|
|
|
|
|
===
|
|
|
|
]]>
|
|
</screen>
|
|
</figure>
|
|
|
|
</sect4>
|
|
|
|
<sect4 id="hd44780-seriallpt-backlight">
|
|
<title>Serial LPT Backlight</title>
|
|
|
|
<para>
|
|
Also a backlight is suported. You will also need a port from the 74HCT14 for
|
|
that. The BL output below should be connected to the BL input in the
|
|
<link linkend="hd44780-connections-backlight">backlight section</link>
|
|
</para>
|
|
|
|
<figure>
|
|
<title>HD44780: Serial LPT - Backlight extra circuit</title>
|
|
<screen>
|
|
<![CDATA[
|
|
|
|
___ 3|\ 4
|
|
Data o-----|___|--+----| >o----o BL output
|
|
LPT-D3 470k | |/
|
|
--- IC1
|
|
---
|
|
|100nF
|
|
|
|
|
===
|
|
|
|
]]>
|
|
</screen>
|
|
</figure>
|
|
|
|
|
|
</sect4>
|
|
|
|
</sect3>
|
|
|
|
<sect3 id="hd44780-picanlcd">
|
|
<title>PIC-an-LCD serial device "picanlcd"</title>
|
|
|
|
<para>
|
|
The PIC-an-LCD module is also supported. It is not connected to the LPT port
|
|
but to a serial port, which saves you from a lot of potential problems.
|
|
To use it, specify the device to which you have connected the module in the
|
|
config file with the Device= setting. The default is /dev/lcd.
|
|
It does not support a keypad nor backlight switching.
|
|
</para>
|
|
|
|
</sect3>
|
|
|
|
<sect3 id="hd44780-lcdserializer">
|
|
<title>LCD serializer device "lcdserializer"</title>
|
|
|
|
<para>
|
|
LCD serializer connection is technically the same of PIC-an-LCD with the same advantages,
|
|
it uses the serial port making things really simple.
|
|
<ulink url="http://www.mindspring.com/~tcoonan/lcd.html">LCD serializer</ulink>
|
|
is not a commercial product like PIC-an-LCD, it's just a project found digging on the net and freely available.
|
|
You have all the tools and the code to build it yourself and to customize the behaviour of the device.
|
|
</para>
|
|
|
|
<sect4 id="hd44780-lcdserializer-whatyouneed">
|
|
<title>What you need</title>
|
|
|
|
<para>
|
|
<itemizedlist>
|
|
<listitem><para>Some electronic knowledge and familiarity with the soldering iron</para></listitem>
|
|
<listitem><para>A PIC16F84 (I used PIC16F84A) or PIC16C54</para></listitem>
|
|
<listitem><para><ulink url="http://jdm.homepage.dk/newpic.htm">JDM PIC programmer</ulink></para></listitem>
|
|
<listitem><para><ulink url="http://gputils.sf.net">gputils</ulink> and <ulink url="http://www.iki.fi/hyvatti/pic/picprog.html">picprog</ulink> installed on your GNU/Linux box</para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
</sect4>
|
|
|
|
<sect4 id="hd44780-lcdserializer-burning">
|
|
<title>Burning the PIC</title>
|
|
|
|
<para>
|
|
First, you need to download the asm source for your pic and then make the hex:
|
|
</para>
|
|
<para>
|
|
<command>
|
|
gpasm lcd16f84_custom.asm
|
|
</command>
|
|
</para>
|
|
<para>
|
|
Now the binary is ready to be flashed to the PIC.
|
|
Connect the programmer with the PIC installed and issue the following command to see it burning ;-):
|
|
</para>
|
|
<para>
|
|
<command>
|
|
picprog --erase --burn --input lcd16f84.hex --pic /dev/ttyS0
|
|
</command>
|
|
</para>
|
|
</sect4>
|
|
|
|
<sect4 id="hd44780-lcdserializer-runninglcdproc">
|
|
<title>Running lcdproc</title>
|
|
|
|
<para>
|
|
It's time to build the <ulink url="http://www.mindspring.com/~tcoonan/lcdpic.html">operating circuit</ulink>,
|
|
remember this driver uses a baud rate of 9600, so JP2 need to be closed.
|
|
</para>
|
|
|
|
<para>
|
|
Now power on the board. You should see OK. on the LCD screen, otherwise, double-check all the connections.
|
|
</para>
|
|
|
|
<para>
|
|
Change LCDd.conf to include the following statments in the hd44780 section:
|
|
</para>
|
|
|
|
<para>
|
|
<screen>
|
|
ConnectionType=lcdserializer
|
|
Device=/dev/ttyS0
|
|
</screen>
|
|
</para>
|
|
|
|
<para>
|
|
Finally, start the daemon and relax watching lcdproc running.
|
|
</para>
|
|
</sect4>
|
|
|
|
<sect4 id="hd44780-lcdserializer-customizemsg">
|
|
<title>Customizing startup message</title>
|
|
|
|
<para>
|
|
If want to change the default startup message (OK.), you can edit the asm source
|
|
and write anything you want.
|
|
Open the asm source with your preferred editor and look for this:
|
|
</para>
|
|
|
|
<para>
|
|
<programlisting>
|
|
<![CDATA[
|
|
;******* START Main Loop Here **************
|
|
|
|
; This is where we should insert any little startup LCD messages...
|
|
; Print "OK." on startup...
|
|
movlw 0x4F
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
movlw 0x4B
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
movlw 0x2E
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
]]>
|
|
</programlisting>
|
|
</para>
|
|
|
|
<para>
|
|
This piece of code sends three characters to the LCD.
|
|
The first line sets the value of w register (working register, aka accumulator) to 0x4F ('O' in ascii). The second line copies this
|
|
value to ARG1, then the value is sent to the LCD. The fourth line delays the execution.
|
|
</para>
|
|
|
|
<para>
|
|
You don't have to write the ascii values in your modification, gpasm does the translation for you, so
|
|
if you want to see Booting... at startup, change the code above to look like this:
|
|
</para>
|
|
|
|
<para>
|
|
<programlisting>
|
|
<![CDATA[
|
|
;******* START Main Loop Here **************
|
|
|
|
; This is where we should insert any little startup LCD messages...
|
|
; Print "Booting..." on startup...
|
|
movlw 'B'
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
movlw 'o'
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
movlw 'o'
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
movlw 't'
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
movlw 'i'
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
movlw 'n'
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
movlw 'g'
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
movlw '.'
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
movlw '.'
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
movlw '.'
|
|
movwf ARG1
|
|
call SendLCDData
|
|
call InitDelay200MS
|
|
]]>
|
|
</programlisting>
|
|
</para>
|
|
|
|
<para>
|
|
Refer to <link linkend="hd44780-lcdserializer-burning">burning section</link> in order to compile and reflash the new firmware.
|
|
</para>
|
|
</sect4>
|
|
</sect3>
|
|
|
|
|
|
<sect3 id="hd44780-bwctusb">
|
|
<title>BWCT USB device "bwctusb"</title>
|
|
|
|
<para>
|
|
The BWCT USB LCD module is also supported. It is not connected to an LPT port
|
|
but to an USB port, which saves you from a lot of potential problems.
|
|
To use it, set the connection type in the config file with the ConnectionType=
|
|
setting to "bwctusb" (without the quotes).
|
|
It does neither support a keypad nor backlight switching but it supports setting
|
|
the display's contrast using the "Contrast" configuration parameter as well as
|
|
specifying which one (of multiple BWCT LCD devices) is wanted using the
|
|
"SerialNumber" configuration parameter.
|
|
</para>
|
|
|
|
</sect3>
|
|
|
|
</sect2>
|
|
|
|
<sect2 id="hd44780-compiling">
|
|
<title>Compiling</title>
|
|
|
|
<para>
|
|
Make sure that the HD44780 files are built when you run configure. This
|
|
can be done by specifying "--enable-drivers=all" or by
|
|
"--enable-drivers=hd44780".
|
|
</para>
|
|
|
|
</sect2>
|
|
|
|
<sect2 id="hd44780-configuration">
|
|
<title>Configuration</title>
|
|
|
|
<para>
|
|
Since LCDproc 0.4.3 the HD44780 driver can be configured from the configfile.
|
|
</para>
|
|
|
|
<para>
|
|
The [HD44780] section is more or less self-explanatory. Yet, a list of the
|
|
possible connection types has proved useful. The following table should make
|
|
it clear, how the ConnectionType is to be set.
|
|
</para>
|
|
|
|
<table>
|
|
<title>HD44780: Connection Types</title>
|
|
<tgroup cols="2">
|
|
<thead>
|
|
<row>
|
|
<entry>Wiring / Display Type</entry>
|
|
<entry>ConnectionType=</entry>
|
|
</row>
|
|
</thead>
|
|
<tbody>
|
|
<row>
|
|
<entry>HD44780 4bit Wiring</entry>
|
|
<entry>4bit</entry>
|
|
</row>
|
|
<row>
|
|
<entry>HD44780 8bit Wiring ("lcdtime")</entry>
|
|
<entry>8bit</entry>
|
|
</row>
|
|
<row>
|
|
<entry>HD44780 Serial LPT Wiring</entry>
|
|
<entry>serialLpt</entry>
|
|
</row>
|
|
<row>
|
|
<entry>HD44780 8bit Wiring "winamp" Style</entry>
|
|
<entry>winamp</entry>
|
|
</row>
|
|
<row>
|
|
<entry>PIC-an-LCD serial device "picanlcd"</entry>
|
|
<entry>picanlcd</entry>
|
|
</row>
|
|
<row>
|
|
<entry>BWCT USB device "bwctusb"</entry>
|
|
<entry>bwctusb</entry>
|
|
</row>
|
|
<row>
|
|
<entry>LCD serializer "lcdserializer"</entry>
|
|
<entry>lcdserializer</entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</table>
|
|
|
|
<tip>
|
|
<para>
|
|
The above table might be outdated, when you read this.
|
|
If you suspect this is the case, you might want to have a look at server/drivers/hd44780-drivers.h
|
|
which contains the actual translation code.
|
|
</para>
|
|
</tip>
|
|
|
|
</sect2>
|
|
|
|
<sect2 id="hd44780-running">
|
|
<title>Running</title>
|
|
|
|
<para>
|
|
Modify the LCDd.conf file before you run LCDd. In this config file are
|
|
detailed instructions on how to configure the HD44780 driver.
|
|
</para>
|
|
|
|
<para>
|
|
Then as usual, start LCDd with the correct config file:
|
|
</para>
|
|
<para>
|
|
E.g. <command>LCDd -c ./LCDd.conf</command>
|
|
</para>
|
|
<para>
|
|
If you want to override the driver selection in LCDd.conf then use:
|
|
</para>
|
|
<para>
|
|
<command>LCDd -c ./LCDd.conf -d HD44780</command>
|
|
</para>
|
|
<para>
|
|
If you use this, the HD44780 driver will read the options from the config
|
|
file anyway.
|
|
</para>
|
|
|
|
</sect2>
|
|
|
|
<sect2 id="hd44780-miscellania">
|
|
<title>Miscellania</title>
|
|
|
|
<para>
|
|
This text has originally been taken from a message by Bill Farrow
|
|
<email>bfarrow@arrow.bsee.swin.edu.au</email>.
|
|
</para>
|
|
|
|
<para>
|
|
Updated February 2000, Benjamin Tse <email>blt@ComPorts.com</email>
|
|
</para>
|
|
|
|
<para>
|
|
Updated October 2001, Joris Robijn <email>joris@robijn.net</email>
|
|
</para>
|
|
|
|
<para>
|
|
Converted to docbook March 2002, Rene Wagner <email>reenoo@gmx.de</email>
|
|
</para>
|
|
|
|
<para>
|
|
Updated April 2002, Rene Wagner <email>reenoo@gmx.de</email>
|
|
</para>
|
|
|
|
</sect2>
|
|
</sect1>
|