* Automatically exclude the pin for switchable backlight from keypad scanning

in the 4bit and 8bit wiring. This fixes problems with flickering backlight if
  a slow parallel port is used. IMPORTANT: This may require a hardware change!
* In code comments use the same line names as in the user's guide (Y1/X1
  instead of Y0/X0).
* Add documentation about hd44780-ftdi's 4bit mode.

ChangeLog

@@ -19,6 +19,7 @@ v.0.5dev (ongoing development)
  * Modify serial drivers to use cfmakeraw
  + hd44780: Add a 'none' charmap which does not replace any character
  * hd44780: Change mapping for spanish 'n with tilde' characters
+ * hd44780: Exclude pin for switchable backlight from keypad scanning
 
 v0.5.3
  + lcdexec: notification when called program finishes

docs/lcdproc-user/drivers/hd44780.docbook

@@ -827,6 +827,7 @@ The optional keypad can be connected as follows:
       <entry namest="lpt1" nameend="lpt2" align="center">printer port</entry>
       <entry morerows="1">&lt;-&gt;</entry>
       <entry align="center">keypad</entry>
+      <entry morerows="1">remarks</entry>
     </row>
     <row>
       <entry>name</entry>
@@ -840,42 +841,49 @@ The optional keypad can be connected as follows:
       <entry>2</entry>
       <entry></entry>
       <entry>Y<subscript>1</subscript></entry>
+      <entry></entry>
     </row>
     <row>
       <entry>D1</entry>
       <entry>3</entry>
       <entry></entry>
       <entry>Y<subscript>2</subscript></entry>
+      <entry></entry>
     </row>
     <row>
       <entry>D2</entry>
       <entry>4</entry>
       <entry></entry>
       <entry>Y<subscript>3</subscript></entry>
+      <entry></entry>
     </row>
     <row>
       <entry>D3</entry>
       <entry>5</entry>
       <entry></entry>
       <entry>Y<subscript>4</subscript></entry>
+      <entry></entry>
     </row>
     <row>
       <entry>D4</entry>
       <entry>6</entry>
       <entry></entry>
       <entry>Y<subscript>5</subscript></entry>
+      <entry></entry>
     </row>
     <row>
       <entry>D5</entry>
       <entry>7</entry>
       <entry></entry>
       <entry>Y<subscript>6</subscript></entry>
+      <entry>Only if not used for backlight or 3<superscript>rd</superscript> controller.</entry>
     </row>
     <row>
       <entry>nSTRB</entry>
       <entry>1</entry>
       <entry></entry>
       <entry>Y<subscript>7</subscript></entry>
+      <entry morerows="3">Only if not used for additional controllers.</entry>
     </row>
     <row>
       <entry>nLF</entry>
@@ -900,30 +908,35 @@ The optional keypad can be connected as follows:
       <entry>10</entry>
       <entry></entry>
       <entry>X<subscript>1</subscript></entry>
+      <entry></entry>
     </row>
     <row>
       <entry>BUSY</entry>
       <entry>11</entry>
       <entry></entry>
       <entry>X<subscript>2</subscript></entry>
+      <entry></entry>
     </row>
     <row>
       <entry>PAPEREND</entry>
       <entry>12</entry>
       <entry></entry>
       <entry>X<subscript>3</subscript></entry>
+      <entry></entry>
     </row>
     <row>
       <entry>SELIN</entry>
       <entry>13</entry>
       <entry></entry>
       <entry>X<subscript>4</subscript></entry>
+      <entry></entry>
     </row>
     <row>
       <entry>nFAULT</entry>
       <entry>15</entry>
       <entry></entry>
       <entry>X<subscript>5</subscript></entry>
+      <entry></entry>
     </row>
   </tbody>
 </tgroup>
@@ -1407,7 +1420,7 @@ The optional keypad can be connected as follows:
       <entry>nSEL</entry>
       <entry>17</entry>
       <entry></entry>
-      <entry>Y<subscript>10</subscript></entry>
+      <entry>Y<subscript>10</subscript> (only if not used for backlight)</entry>
     </row>
     <row>
       <entry>nACK</entry>
@@ -1858,6 +1871,106 @@ The wiring of the control lines can optionally be reconfigured,
 please look at the driver source if you really need that.
 </para>
 
+<para>
+Alternatively you can use a single channel FTDI FT245BM USB &lt;-&gt; parallel
+FIFO chip and use the display in its 4 bit mode.
+</para>
+
+<table id="hd44780-ftdi.4bit-mapping">
+<title>HD44780: 4bit FTDI</title>
+<tgroup cols="5" align="left">
+<colspec colname="ftdi1"/>
+<colspec colname="ftdi2" align="right"/>
+<colspec colname="base" align="center"/>
+<colspec colname="lcd1"/>
+<colspec colname="lcd2"/>
+  <thead>
+    <row>
+      <entry namest="ftdi1" nameend="ftdi2" align="center">FTDI chip</entry>
+      <entry morerows="1">&lt;-&gt;</entry>
+      <entry namest="lcd1" nameend="lcd2" align="center">LCD</entry>
+    </row>
+    <row>
+      <entry>name</entry>
+      <entry>pin</entry>
+      <entry>name</entry>
+      <entry>pin</entry>
+    </row>
+  </thead>
+  <tbody>
+    <row>
+      <entry>D0</entry>
+      <entry>25</entry>
+      <entry></entry>
+      <entry>D4</entry>
+      <entry>11</entry>
+    </row>
+    <row>
+      <entry>D1</entry>
+      <entry>24</entry>
+      <entry></entry>
+      <entry>D5</entry>
+      <entry>12</entry>
+    </row>
+    <row>
+      <entry>D2</entry>
+      <entry>23</entry>
+      <entry></entry>
+      <entry>D6</entry>
+      <entry>13</entry>
+    </row>
+    <row>
+      <entry>D3</entry>
+      <entry>22</entry>
+      <entry></entry>
+      <entry>D7</entry>
+      <entry>14</entry>
+    </row>
+    <row>
+      <entry>D4</entry>
+      <entry>21</entry>
+      <entry></entry>
+      <entry>EN</entry>
+      <entry>6</entry>
+    </row>
+    <row>
+      <entry>D5</entry>
+      <entry>20</entry>
+      <entry></entry>
+      <entry>RS</entry>
+      <entry>4</entry>
+    </row>
+    <row>
+      <entry>D6</entry>
+      <entry>19</entry>
+      <entry></entry>
+      <entry>RW</entry>
+      <entry>5</entry>
+    </row>
+  </tbody>
+</tgroup>
+</table>
+
+<para>
+The following special configuration settings are required to use a single
+channel FTDI FIFO chip:
+</para>
+
+<example id="hd44780-ftdi-4bit-config.example">
+<title>HD44780: Configuration for FTDI 4bit</title>
+<screen>
+<![CDATA[
+[hd44780]
+ConnectionType=ftdi
+ftdi_mode=4
+ftdi_line_RS=0x40
+ftdi_line_RW=0x20
+ftdi_line_EN=0x10
+]]>
+</screen>
+</example>
+
+
 </sect3>
 
 <sect3 id="hd44780-lis2">
@@ -2706,7 +2819,8 @@ This can be done by specifying <option>--enable-drivers=all</option> or by inclu
       <emphasis><parameter><literal>hd44780_default</literal></parameter></emphasis> |
       <parameter><literal>hd44780_euro</literal></parameter> |
       <parameter><literal>ea_ks0073</literal></parameter> |
-      <parameter><literal>sed12780f_0b</literal></parameter>
+      <parameter><literal>sed12780f_0b</literal></parameter> |
+      <parameter><literal>none</literal></parameter>
     }
   </term>
   <listitem><para>
@@ -2729,6 +2843,12 @@ This can be done by specifying <option>--enable-drivers=all</option> or by inclu
         <listitem><para>
           <literal>sed12780f_0b</literal> is for some SED 1278 displays.
         </para></listitem>
+        <listitem><para>
+          The <literal>none</literal> charmap does not translate any characters.
+          It displays the characters the display controllers actually has
+          stored in its CGROM for that position instead. This setting is
+          intended for debugging purpose.
+        </para></listitem>
       </itemizedlist>
       You only need to set this parameter if you have a non-standard
       HD44780 display.

server/drivers/hd44780-4bit.c

@@ -34,19 +34,29 @@
  * Keypad connection (optional):
  * Some diodes and resistors are needed, see further documentation.
  * printer port   keypad
- * D0 (2)	  Y0
+ * D0 (2)	  Y1
- * D1 (3)	  Y1
+ * D1 (3)	  Y2
- * D2 (4)	  Y2
+ * D2 (4)	  Y3
- * D3 (5)	  Y3
+ * D3 (5)	  Y4
- * D4 (6)	  Y4
+ * D4 (6)	  Y5
- * D5 (7)	  Y5
+ *
+ * With a backlight or three displays, 4 additional rows are possible:
  * nSTRB (1)      Y6
  * nLF  (14)      Y7
  * INIT (16)      Y8
  * nSEL (17)      Y9
+ *
+ * With only two controllers and no backlight, 5 additional rows are possible:
+ * D5 (7)	  Y6
+ * nSTRB (1)      Y7
+ * nLF  (14)      Y8
+ * INIT (16)      Y9
+ * nSEL (17)      Y10
+ *
+ * Colums return lines are the same for all configurations:
  * nACK (10)      X0
  * BUSY (11)      X1
- * PAPEREND (12   X2
+ * PAPEREND (12)  X2
  * SELIN (13)     X3
  * nFAULT (15)    X4
  *
@@ -125,7 +135,7 @@ hd_init_4bit(Driver *drvthis)
 	port_out(p->port, 0x03);
 	if (p->delayBus) hd44780_functions->uPause(p, 1);
 
-	/* We'll now send 0x03 a coulpe of times, 
+	/* We'll now send 0x03 a coulpe of times,
 	 * which is in fact (FUNCSET | IF_8BIT) >> 4 */
 	port_out(p->port, enableLines | 0x03);
 	port_out(p->port + 2, ALLEXT ^ OUTMASK);
@@ -268,22 +278,35 @@ unsigned char lcdstat_HD44780_readkeypad(PrivateData *p, unsigned int YData)
 {
 	unsigned char readval;
 
-	// 10 bits output or 6 bits if >=3 displays
+	/* If at most two controllers and NO backlight, 10 bits may be used */
-	// Convert the positive logic to the negative logic on the LPT port
+	if ((p->numDisplays <= 2) && (!p->have_backlight)) {
-	port_out(p->port, ~YData & 0x003F);
+		port_out(p->port, ~YData & 0x003F);
-	if (p->numDisplays<=3) {
-		// Can't combine >3 displays with >6 keypad output lines
 		port_out(p->port + 2, (((~YData & 0x03C0) >> 6)) ^ OUTMASK);
 	}
+	else {
+		/*
+		 * Else ignore D5, because it may be either backlight or EN3.
+		 * Note: If three displays are used, have_backlight must be
+		 * set to 'no' in the config.
+		 */
+		port_out(p->port, (~YData & 0x001F) | p->backlight_bit);
+		/*
+		 * With at most three controllers or backlight 9 bits may be
+		 * used.
+		 */
+		if (p->numDisplays<=3) {
+			port_out(p->port + 2, (((~YData & 0x01E0) >> 5)) ^ OUTMASK);
+		}
+	}
 	if (p->delayBus) p->hd44780_functions->uPause(p, 1);
 
-	// Read inputs
+	/* Read inputs */
 	readval = ~ port_in(p->port + 1) ^ INMASK;
 
-	// Put port back into idle state for backlight
+	/* Put port back into idle state for backlight */
 	port_out(p->port, p->backlight_bit);
 
-	// And convert value back (MSB first).
+	/* And convert value back (MSB first) */
 	return (((readval & FAULT) / FAULT <<4) |		/* pin 15 */
 		((readval & SELIN) / SELIN <<3) |		/* pin 13 */
 		((readval & PAPEREND) / PAPEREND <<2) |		/* pin 12 */

server/drivers/hd44780-ext8bit.c

@@ -27,21 +27,21 @@
  * Keypad connection (optional):
  * Some diodes and resistors are needed, see further documentation.
  * printer port   keypad
- * D0 (2)	  Y0
+ * D0 (2)	  Y1
- * D1 (3)	  Y1
+ * D1 (3)	  Y2
- * D2 (4)	  Y2
+ * D2 (4)	  Y3
- * D3 (5)	  Y3
+ * D3 (5)	  Y4
- * D4 (6)	  Y4
+ * D4 (6)	  Y5
- * D5 (7)	  Y5
+ * D5 (7)	  Y6
- * D6 (8)	  Y6
+ * D6 (8)	  Y7
- * D7 (9)	  Y7
+ * D7 (9)	  Y8
- * nSTRB  (1)     Y8
+ * nSTRB  (1)     Y9
- * nSEL   (17)    Y9
+ * nSEL   (17)    Y10 (optional, only if no backlight is used)
- * nACK   (10)    X0
+ * nACK   (10)    X1
- * BUSY   (11)    X1
+ * BUSY   (11)    X2
- * PAPEREND (12)  X2
+ * PAPEREND (12)  X3
- * SELIN  (13)    X3
+ * SELIN  (13)    X4
- * nFAULT (15)    X4
+ * nFAULT (15)    X5
  *
  * Created modular driver Dec 1999, Benjamin Tse <blt@Comports.com>
  *
@@ -179,7 +179,7 @@ void lcdtime_HD44780_backlight(PrivateData *p, unsigned char state)
 /**
  * Read keypress.
  * \param p      Pointer to driver's private data structure.
- * \param YData  ???
+ * \param YData  Bitmap of rows / lines to enable.
  * \return       Bitmap of the pressed keys.
  */
 unsigned char lcdtime_HD44780_readkeypad(PrivateData *p, unsigned int YData)
@@ -188,19 +188,19 @@ unsigned char lcdtime_HD44780_readkeypad(PrivateData *p, unsigned int YData)
 
 	sem_wait(semid);
 
-	// 10 bits output or 8 bits if >=2 displays
 	// Convert the positive logic to the negative logic on the LPT port
 	port_out(p->port, ~YData & 0x00FF);
-	if (p->numDisplays<=2) {
+	// 9 bits output if backlight is used, 10 bits otherwise
-		// Can't combine >3 displays with >8 keypad output lines
+	if (p->have_backlight)
+		port_out(p->port + 2, (((~YData & 0x0100) >> 8) | p->backlight_bit) ^ OUTMASK);
+	else
 		port_out(p->port + 2, (((~YData & 0x0100) >> 8) | ((~YData & 0x0200) >> 6)) ^ OUTMASK);
-	}
 	if (p->delayBus) p->hd44780_functions->uPause(p, 1);
 
 	// Read inputs
 	readval = ~ port_in(p->port + 1) ^ INMASK;
 
-	// Put port back into idle state for backlight
+	// Put port back into idle state
 	port_out(p->port, p->backlight_bit ^ OUTMASK);
 	sem_signal(semid);
 

server/drivers/hd44780-serialLpt.c

@@ -31,19 +31,19 @@
  * Keypad connection (optional):
  * This is connected on the 4094 parallel to the LCD.
  * Some diodes and resistors are needed, see further documentation.
- * Q1 (4)	  Y0
+ * Q1 (4)	  Y1
- * Q2 (5)	  Y1
+ * Q2 (5)	  Y2
- * Q3 (6)	  Y2
+ * Q3 (6)	  Y3
- * Q4 (7)	  Y3
+ * Q4 (7)	  Y4
- * Q5 (14)	  Y4
+ * Q5 (14)	  Y5
- * Q6 (13)	  Y5
+ * Q6 (13)	  Y6
- * Q7 (12)	  Y6
+ * Q7 (12)	  Y7
  * The 'output' of the keys should be connected to the following LPT pins:
- * nACK   (10)    X0
+ * nACK   (10)    X1
- * BUSY   (11)    X1
+ * BUSY   (11)    X2
- * PAPEREND (12)  X2
+ * PAPEREND (12)  X3
- * SELIN  (13)    X3
+ * SELIN  (13)    X4
- * nFAULT (15)    X4
+ * nFAULT (15)    X5
  * If you want to use as few LPT lines as possible, only use X0.
  *
  * This file is released under the GNU General Public License. Refer to the

server/drivers/hd44780-winamp.c

@@ -46,19 +46,19 @@
  * Keypad connection (optional):
  * Some diodes and resistors are needed, see further documentation.
  * printer port   keypad
- * D0 (2)	  Y0
+ * D0 (2)	  Y1
- * D1 (3)	  Y1
+ * D1 (3)	  Y2
- * D2 (4)	  Y2
+ * D2 (4)	  Y3
- * D3 (5)	  Y3
+ * D3 (5)	  Y4
- * D4 (6)	  Y4
+ * D4 (6)	  Y5
- * D5 (7)	  Y5
+ * D5 (7)	  Y6
- * D6 (8)	  Y6
+ * D6 (8)	  Y7
- * D7 (9)	  Y7
+ * D7 (9)	  Y8
- * nACK   (10)    X0
+ * nACK   (10)    X1
- * BUSY   (11)    X1
+ * BUSY   (11)    X2
- * PAPEREND (12)  X2
+ * PAPEREND (12)  X3
- * SELIN  (13)    X3
+ * SELIN  (13)    X4
- * nFAULT (15)    X4
+ * nFAULT (15)    X5
  */
 
 #include "hd44780-winamp.h"