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HD44780 general:

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- Removed 'long p' from keymap

HD44780 serialLpt:
- Backlight support
- Updated documentation
This commit is contained in:
robijn
2001-12-09 14:33:17 +00:00
parent d0511bb7d8
commit 3929662434
3 changed files with 122 additions and 37 deletions
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docs/hd44780_howto.txt
+64 -10
View File
@@ -73,6 +73,7 @@ You can connect a keypad with all connection types. The maximum supported
number of keys differs per type. There are several ways to connect the keys
to the input pins.
1.1.2.1 Direct keys
--------------------
@@ -168,10 +169,29 @@ You can buy arrays of keys that are connected like this in the electronics
shop. They usually call it a matrix keypad. To hook it to lcdproc, you
would only need to add the resistors and diodes.
If you want to use just one return line, for example with the serialLpt
wiring, it looks (completely drawn) like this:
O 5V
|
.-.
| | 4k7 or 22k
diodes | |
1N4148 '-'
___ |
Y0 o---|<---o o---+
___ |
Y1 o---|<---o o---+
___ |
Y2 o---|<---o o---+
___ |
Y3 o---|<---o o---+----o return line
If the driver generates keypresses without that you actually press a key,
it might be that the unconnected input lines are picking up
electromagnetic waves from the air. In that case connect the unconnected
input lines (pin 10, 11, 12, 13 and 15 of the LPT) to VCC.
electromagnetic waves from the air. In that case connect the unconnected
input lines (pin 10, 11, 12, 13 and 15 of the LPT) to VCC = 5V.
1.1.3 Backlight
@@ -200,7 +220,7 @@ LPT Sub-D connector | 4k7 |
=== GND
Note: 4k7 means 4,7 kohm and 330E means 330 ohm.
The BC327 has the following connections:
The BC327 transistor has the following connections:
_____
| |
@@ -216,6 +236,11 @@ the side. If that is the case, there is usually NO RESISTOR present to limit
the current through the LEDs. Therefor you should add a resistor after
the transistor of 10 ohm.
If you want the backlight to light a bit while it's switched 'off', you can
add a resistor bypassing the transistor from e to c, with a value of, say
47ohm or 22ohm. (My 4x20 has an internal resistor of 6ohm, so with 47 ohm
extra it lights at only 1/9th. I like this. Joris.)
1.2 4-bit
----------
@@ -387,11 +412,11 @@ cannot use the backlight control together with the bargraph.
This interface uses a handful of wires to interface to the
HD44780. Suitable for high noise, long connections. Designed by
Andrew McMeikan <andrewm@engineer.com>. The original wiring and
driver can be found at:
driver can be found at:
http://members.xoom.com/andrewmuck
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).
keys again (it had earlier supported keys, but some time did not).
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 ! :)
@@ -400,7 +425,7 @@ 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.
this wiring.
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
@@ -508,7 +533,14 @@ complex. If you do not understand the schematic, do not build it.
|
=== GND
Also the serialLpt wiring supports a keypad. The 3 wires version supports
1.5.1 Keypad
------------
To understand this part of the serialLpt documentation, you also need to
read the keypad section in this document.
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.
@@ -521,8 +553,30 @@ The return lines are the following:
SELIN (13) X3
nFAULT (15) X4
To understand some of this keypad documentation, do also read the keypad
section in this document.
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:
1|\ 2 13|\ 12 ___
keypad o-----| >o------| >o---|___|---+---o input pin on LPT port
return |/ |/ 220E |
IC1 IC1 ---
--- 1nF
|
===
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 paragraph
1.1.3.
___ 3|\ 4
Data o-----|___|--+----| >o----o BL output
LPT-D3 470k | |/
--- IC1
---
|100nF
|
===
2. Compiling
@@ -544,7 +598,7 @@ Then as usual, start LCDd with the correct config file:
for example.
If you want to override the driver selection in LCDd.conf then use:
LCDd -c ./LCDd.conf -d HD44780
LCDd -c ./LCDd.conf -d HD44780
If you use this, the HD44780 driver will read the options from the config
file.
server/drivers/hd44780-charmap.h
+14 -6
View File
@@ -7,13 +7,21 @@
* Initial table taken from lcd.o Linux kernel driver by
* Nils Faerber <nilsf@users.sourceforge.net>. Thanks!
*
* Alternative mappings used:
* #112 ("p") -> #240 (large "p"), orig. mapped -> #112
* #113 ("q") -> #241 (large "q"), orig. mapped -> #113
*
* This file is released under the GNU General Public License. Refer to the
* COPYING file distributed with this package.
*
*
* Following translations are being performed:
* - maps umlaut accent characters to the corresponding umlaut characters
* - maps other accent characters to the characters without accents
* - maps beta (=ringel-S), micro and Yen
*
* Alternative mappings:
* - #112 ("p") -> #240 (large "p"), orig. mapped -> #112
* - #113 ("q") -> #241 (large "q"), orig. mapped -> #113
*
* HD44780 misses backslash
*
*/
const char HD44780_charmap[]={
@@ -44,7 +52,7 @@ const char HD44780_charmap[]={
84, 85, 86, 87,
88, 89, 90, 91,
/* #92 */
92, 93, 94, 95,
47, 93, 94, 95,
96, 97, 98, 99,
100,101,102,103,
104,105,106,107,
@@ -63,7 +71,7 @@ const char HD44780_charmap[]={
152,153,154,155,
156,157,158,159,
/* #160 */
160, 33,236,163,
160, 33,236,237,
164, 92,124,167,
34,169,170,171,
172,173,174,175,
server/drivers/hd44780-serialLpt.c
+44 -21
View File
@@ -74,6 +74,7 @@ void shiftreg (unsigned char displayID, unsigned char r);
#define EN2 32
static unsigned int lptPort;
static char backlight_bit = 0;
// Initialisation
int
@@ -91,21 +92,21 @@ hd_init_serialLpt (HD44780_functions * hd44780_functions, lcd_logical_driver * d
hd44780_functions->backlight = lcdserLpt_HD44780_backlight;
hd44780_functions->scankeypad = lcdserLpt_HD44780_scankeypad;
// Clear the shiftregister
rawshift (0);
// setup the lcd in 4 bit mode
shiftreg (enableLines, 3);
hd44780_functions->uPause (4100);
hd44780_functions->uPause (15000);
shiftreg (enableLines, 3);
hd44780_functions->uPause (5000);
shiftreg (enableLines, 3);
hd44780_functions->uPause (100);
shiftreg (enableLines, 3);
hd44780_functions->uPause (40);
hd44780_functions->uPause (100);
shiftreg (enableLines, 2);
hd44780_functions->uPause (40);
hd44780_functions->uPause (100);
hd44780_functions->senddata (0, RS_INSTR, FUNCSET | IF_4BIT | TWOLINE | SMALLCHAR);
@@ -135,42 +136,59 @@ lcdserLpt_HD44780_senddata (unsigned char displayID, unsigned char flags, unsign
shiftreg (enableLines, portControl | h);
shiftreg (enableLines, portControl | l);
// Restore line status for backlight
port_out (lptPort, backlight_bit );
}
void
lcdserLpt_HD44780_backlight (unsigned char state)
{
// Store new state
backlight_bit = (state?LCDDATA:0);
// Set line status for backlight
port_out (lptPort, backlight_bit );
}
unsigned char lcdserLpt_HD44780_scankeypad ()
{
// Unfortunately just bit shifting does not work with the 2 IC version...
// Unfortunately just bit shifting does not work with the 2-wire version...
unsigned char keybits;
unsigned int shiftcount;
unsigned int shiftingbit;
unsigned char readval, inputs_zero, r;
unsigned char readval, inputs_zero;
int i;
unsigned int scancode = 0;
// While scanning the keypad, the 2-wire version executes the 0xFF
// command. This command sets the cursor position, so it's harmless.
// I could not prevent this, while staying compatible with both
// wiring versions.
r = 0xFF; // This command will set the cursor position, so it's harmless
// Clear the shiftregister, needed for 3-wire version
rawshift(0);
hd44780_functions->uPause (2);
readval = ~ port_in (lptPort + 1) ^ INMASK;
inputs_zero = ( (readval >> 4 & 0x03) | (readval >> 5 & 0x04) | (readval >> 3 & 0x08) | (readval << 1 & 0x10) );
if( inputs_zero == 0 ) {
// No keys were pressed
// Restore line status for backlight.
port_out (lptPort, backlight_bit );
return 0;
}
// Scan the keypad while sending the first half of the command (high nibble)
for (i = 7; i >= 0; i--) { /* MSB first */
port_out (lptPort, ((r >> i) & 1) * LCDDATA); /*set up data */
port_out (lptPort, (((r >> i) & 1) * LCDDATA) | LCDCLOCK); /*rising edge of clock */
for (i = 7; i >= 0; i--) { /* MSB first */
port_out (lptPort, LCDDATA); /*set up data */
port_out (lptPort, LCDDATA | LCDCLOCK); /*rising edge of clock */
hd44780_functions->uPause (2);
// Do keyscan too !
if( !scancode ) {
// Read input line(s)
readval = ~ port_in (lptPort + 1) ^ INMASK;
@@ -188,12 +206,18 @@ unsigned char lcdserLpt_HD44780_scankeypad ()
}
}
hd44780_functions->uPause (4);
// Wait for 2-wire version to clear the latch...
hd44780_functions->uPause (6);
// And again for the second half of the command (low nibble)
rawshift (r);
// And again for the second half of the command (low nibble).
// Needed for 2-wire version.
rawshift (0xFF);
hd44780_functions->uPause (4);
// Wait for 2-wire version to clear the latch...
hd44780_functions->uPause (6);
// Restore line status for backlight.
port_out (lptPort, backlight_bit );
return scancode;
}
@@ -203,7 +227,6 @@ void
rawshift (unsigned char r)
{
int i;
// r |= 0x80; // just to make sure ...
for (i = 7; i >= 0; i--) { /* MSB first */
port_out (lptPort, ((r >> i) & 1) * LCDDATA); /*set up data */
@@ -215,9 +238,9 @@ rawshift (unsigned char r)
void
shiftreg (unsigned char enableLines, unsigned char r)
{
rawshift (r | 0x80); // highest bit always set to 1 for Clear for wiring with 2 ICs
rawshift (r | 0x80); // highest bit always set to 1 for Clear for 2-wire version
port_out (lptPort, enableLines); // latch it, to correct display
hd44780_functions->uPause (1);
port_out (lptPort, 0); // for wiring with 1 IC
hd44780_functions->uPause (3);
port_out (lptPort, 0); // for 3-wire version
hd44780_functions->uPause (5); // wait for 2-wire version to clear the latch...
}