Added details for the modular hd44780 driver. Documents the four wiring
methods that the driver supports.
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blt
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(this text taken from a message by Bill Farrow, more info coming later)
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<bfarrow@arrow.bsee.swin.edu.au>
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HD44780 HOWTO
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-------------
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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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The LCDproc HD44780 driver supports the following connections on a
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parallel port:
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- 4-bit
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- 8-bit (winamp style)
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- extended 8-bit (LCD + LED bargraph)
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- serial LPT
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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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The code in LCDproc for the hd4470 LCD controller chips comes from
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"lcdtext" (by Matthias Prinke) or one of the derivatives ("lcdstat4",
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"lcdtime").
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1. Connections
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--------------
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You might like to get those packages down as well and have a play.
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1.1 Power
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----------
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LCDproc-0.4 only supports 4 line displays, but LCDproc-0.3.5 runs 2 line
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displays also. A different maintainer is responsible for this version.
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All variants use the same method of obtaining power. i.e., for each LCD:
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The pinouts are like so : (From lcdtext)
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1.1 Connecting the LCD to a printer port
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-----------------------------------------
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LCD printer port
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Pin signal Pin signal
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1 GND 18..25 GND
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2 +5V --- *)
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3 Vadj. --- *)
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4 RS 6 D4
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5 RW 7 D5
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6 EN 8 D6
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11 D4 2 D0
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12 D5 3 D1
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13 D6 4 D2
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14 D7 5 D3
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LCD pin signal
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1 GND (connect to any of pins 18 - 25 of you parallel port)
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2 +5V
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3 Vadj (contrast)
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Getting the supply voltage:
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Use a floppy supply connector, get it from the game port, take some
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diodes and a capacitor and get it from the port's data lines, get it
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from the keyboard connector or whatever you like. Be save to avoid
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short circuit. You need only 3mA at 5V! (if you have the same type
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lcd)
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from the keyboard connector or whatever you like. Be safe to avoid
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a short circuit. Most non-backlit displays only need 3mA at 5V!
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Connecting the contrast adjusting pin (Vadj.):
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@@ -47,3 +47,147 @@ Connecting the contrast adjusting pin (Vadj.):
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Vadj.
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1.2 4-bit
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----------
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This is originally based on "lcdtext" (by Matthias Prinke).
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The pinouts are:
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printer port LCD
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D0 (2) D4 (11)
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D1 (3) D5 (12)
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D2 (4) D6 (13)
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D3 (5) D7 (14)
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D4 (6) RS (4)
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D5 (7) RW (5) (LCD3 - 6) (optional - pull all LCD RW low)
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D6 (8) EN (6)
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D7 (9) EN2 (LCD2 - 6) (optional)
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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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printer port LCD
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STR (1) EN4
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LF (14) EN5
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INIT (16) EN6
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SEL (17) EN7
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1.3 8-bit
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----------
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This type of connection should work with winamp.
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printer port LCD
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D0 (2) D0 (7)
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D1 (3) D1 (8)
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D2 (4) D2 (9)
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D3 (5) D3 (10)
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D4 (6) D4 (11)
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D5 (7) D5 (12)
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D6 (8) D6 (13)
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D7 (9) D7 (14)
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nSTRB (1) EN (6)
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nLF (14) nRW (5) (EN3 6 - LCD 3) (optional)
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INIT (16) RS (4)
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nSEL (17) EN2 (6 - LCD 2) (optional)
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If you only want one display, wire nLF (pin 14) to nRW of your LCD.
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N.B. I haven't tried using winamp while having the third LCD connected
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to this line.
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1.4 Extended 8-bit
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-------------------
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This is originally based on "lcdtime" (by Benjamin Tse
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<blt@ComPorts.com>) and allows you to combine the LCD with a LED
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bargraph. The LCD is driven by LCDproc and the LEDs by another program
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such as portato. Further details can be obtained from:
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http://metalab.unc.edu/pub/linux/system/status/lcdtime-0.2.tar.gz
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http://metalab.unc.edu/pub/linux/system/status/meter-0.2.tar.gz
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http://metalab.unc.edu/pub/linux/system/status/portato-1.2.tar.gz
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The LCD connections are:
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printer port LCD
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D0 (2) D0 (7)
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D1 (3) D1 (8)
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D2 (4) D2 (9)
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D3 (5) D3 (10)
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D4 (6) D4 (11)
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D5 (7) D5 (12)
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D6 (8) D6 (13)
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D7 (9) D7 (14)
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nSEL (17) -
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nSTRB (1) RS (4)
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nLF (14) RW (5) (LCD2 - 6) (optional - pull all LCD RW low)
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INIT (16) EN (6)
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See the lcdtime tar-ball (above) for full details of the bargraph
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connections.
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1.5 Serial LPT
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---------------
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This interface uses a handful of wires to interface to the
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HD44780. Suitable for high noise, long connections. Designed by
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Andrew McMeikan <andrewm@engineer.com>. Refer to
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http://members.xoom.com/andrewmuck for details of the connections.
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2. Compiling
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------------
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Make sure that the HD44780 files are built when you run configure. This
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can be done by specifying "--enable-drivers=all" or by
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"--enable-drivers=hd44780".
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3. Running
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----------
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Keep in mind the following points.
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- When specifying the lcd size, do so before the -d argument.
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- Arguments that need to be passed to the driver should be in quotes after
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the -d HD44780 arguments.
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- Use the "-e" argument for extended interfaces (e.g. >= 3 displays as
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indicated by "optional" connections above).
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EXAMPLES:
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For a 4bit connection, 16x2 display on port 0x278
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LCDd -t 16x2 -d HD44780 "-p 0x278"
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For a 4bit, 40x4 display (effectively two 40x2 displays)
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LCDd -t 40x4 -d HD44780 "-v 2,2"
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For a Winamp connection, 20x2 and 20x1 displays
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LCDd -t 20x3 -d HD44780 "-c winamp -v 2,1"
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For a 4bit, 16x2, 16x4 and 16x1 displays
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LCDd -t 16x7 -d HD44780 "-v 2,4,1 -e"
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For help on the parameters for the 8-bit driver (make sure --help is the
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last arguments in quotes):
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LCDd -d HD44780 "-c 8bit --help"
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4. Miscellania
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---------------
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This text originally taken from a message by Bill Farrow
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<bfarrow@arrow.bsee.swin.edu.au>.
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Updated February 2000, Benjamin Tse (blt@ComPorts.com)
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