HD44780 general:
- Removed 'long p' from keymap HD44780 serialLpt: - Backlight support - Updated documentation
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robijn
+64
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@@ -73,6 +73,7 @@ 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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1.1.2.1 Direct keys
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--------------------
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@@ -168,10 +169,29 @@ 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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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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O 5V
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|
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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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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.
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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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1.1.3 Backlight
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@@ -200,7 +220,7 @@ LPT Sub-D connector | 4k7 |
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=== GND
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Note: 4k7 means 4,7 kohm and 330E means 330 ohm.
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The BC327 has the following connections:
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The BC327 transistor has the following connections:
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_____
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| |
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@@ -216,6 +236,11 @@ 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 add a resistor after
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the transistor of 10 ohm.
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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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1.2 4-bit
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----------
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@@ -387,11 +412,11 @@ cannot use the backlight control together with the bargraph.
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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>. The original wiring and
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driver can be found at:
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driver can be found at:
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http://members.xoom.com/andrewmuck
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I (Joris) have extended this driver and the wiring a bit. It now supports
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keys again (it had earlier supported keys, but some time did not).
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keys again (it had earlier supported keys, but some time did not).
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Further I have extended the driver and the wiring to be able to run
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using 2 instead of 3 output pins. That's even one less pin ! :)
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@@ -400,7 +425,7 @@ Of course the use of fewer lines than the other wirings can not stay
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without drawbacks. In this case the simplicity of the long feeding wires
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is compensated by some intelligence in the decoding of the data. If you
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have no experience with the soldering iron, I do not recommend to build
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this wiring.
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this wiring.
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OK, so here is the wiring. First of the 'simple' 3 wires version. IC1 is
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the shift register, a 4094. Do not forget to connect the 5V to pin 16 and
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@@ -508,7 +533,14 @@ complex. If you do not understand the schematic, do not build it.
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=== GND
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Also the serialLpt wiring supports a keypad. The 3 wires version supports
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1.5.1 Keypad
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------------
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To understand this part of the serialLpt documentation, you also need to
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read the keypad section in this document.
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serialLpt wiring supports a keypad. The 3 wires version supports
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8 keys, or if you use multiple return lines up to 8 x 5 = 40 lines. The
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2 wires version supports 7 keys, or with multiple return lines
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7 x 5 = 35 keys.
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@@ -521,8 +553,30 @@ The return lines are the following:
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SELIN (13) X3
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nFAULT (15) X4
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To understand some of this keypad documentation, do also read the keypad
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section in this document.
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On lines longer than, say a meter, you should buffer the return line(s).
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If you only have 1 return line, you can buffer it with two remaining
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buffers from the 74HCT14:
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1|\ 2 13|\ 12 ___
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keypad o-----| >o------| >o---|___|---+---o input pin on LPT port
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return |/ |/ 220E |
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IC1 IC1 ---
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--- 1nF
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===
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Also a backlight is suported. You will also need a port from the 74HCT14 for
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that. The BL output below should be connected to the BL input in paragraph
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1.1.3.
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___ 3|\ 4
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Data o-----|___|--+----| >o----o BL output
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LPT-D3 470k | |/
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--- IC1
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---
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|100nF
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===
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2. Compiling
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@@ -544,7 +598,7 @@ Then as usual, start LCDd with the correct config file:
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for example.
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If you want to override the driver selection in LCDd.conf then use:
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LCDd -c ./LCDd.conf -d HD44780
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LCDd -c ./LCDd.conf -d HD44780
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If you use this, the HD44780 driver will read the options from the config
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file.
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