HD44780 general:

- Removed 'long p' from keymap

HD44780 serialLpt:
- Backlight support
- Updated documentation

docs/hd44780_howto.txt

@@ -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.
+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
 ----------
@@ -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
+On lines longer than, say a meter, you should buffer the return line(s).
-section in this document.
+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

server/drivers/hd44780-charmap.h

@@ -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

@@ -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      */
+	for (i = 7; i >= 0; i--) {				/* MSB first  */
-		port_out (lptPort, ((r >> i) & 1) * LCDDATA);			/*set up data   */
+		port_out (lptPort, LCDDATA);			/*set up data */
-		port_out (lptPort, (((r >> i) & 1) * LCDDATA) | LCDCLOCK);	/*rising edge of clock   */
+		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)
+	// And again for the second half of the command (low nibble).
-	rawshift (r);
+	// 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
+	port_out (lptPort, 0);			// for 3-wire version
-	hd44780_functions->uPause (3);
+	hd44780_functions->uPause (5);		// wait for 2-wire version to clear the latch...
 }