Lcd protocol 1.6 - Revision history

Cartridge1987 at 14:46, 30 November 2015

2015-11-30T14:46:44Z

Rew: /* write ports */

2013-11-30T11:20:32Z

write ports

Rew: /* write ports */

2013-11-28T08:17:39Z

write ports

Rew at 16:54, 23 November 2013

2013-11-23T16:54:16Z

Rew: /* read ports */

2013-10-20T15:00:54Z

read ports

Rew: /* write ports */

2013-10-20T14:54:04Z

write ports

Rew: /* write ports */

2013-07-06T20:11:46Z

write ports

Rew: /* write ports */

2013-07-06T20:11:28Z

write ports

Rew: /* write ports */

2013-07-04T15:41:20Z

write ports

Rew: /* write ports */

2013-07-04T11:52:52Z

write ports

@@ Line 11: / Line 11: @@
-= write ports =
+= Write ports =
 Some ports just set a single value. So writing more than one byte to such a port is redundant. Other ports are logically a stream of bytes. So writing more than one byte is encouraged.
@@ Line 56: / Line 56: @@
 (*) These values are written to the eeprom. If you write "0xff", the value will be interpreted as "empty eeprom" on next boot, and the default will be used.
-= read ports =
+= Read ports =
 The lcd boards support several read ports:
@@ Line 75: / Line 75: @@
 |}
-= startup message =
+= Startup message =
 The startup message is stored in eeprom. It will be shown in the future when you power up your display.
@@ Line 89: / Line 89: @@
 To clear the startup message send a single "0xff". For each line you care about. The current version will show the default message if the first character of the first line is 0xff. Later versions might decide on a per-line basis.
-= examples =
+= Examples =
-== read identification ==
+== Read identification ==
 read the identification string of the board. ('spi_lcd 1.3').
@@ Line 133: / Line 133: @@
 |}
-== set cursor position ==
+== Set cursor position ==
 move to line 1, character 5:
 {| border=1
@@ Line 145: / Line 145: @@
 |}
-== define custom character ==
+== Define custom character ==
 A usage of the 0x01 port is to define custom characters. Here in a less verbose format:
@@ Line 159: / Line 159: @@
 the last two lines are just a example of how to get back to "display" mode. It works for me I don't have the inclination to find other ways.
-== scrolling the display ==
+== Scrolling the display ==
 Send

@@ Line 35: / Line 35: @@
 | 0x11 || move the cursor to line l, position p. <br>l is the top 3 bits<br>p is the bottom 5 bits of the data.<br>Both are zero-based. The top line is line 0, the left character is char 0.
 |-
-| 0x12 || set contrast. Is written to EEPROM.
+| 0x12 || set contrast. Is written to EEPROM.  (*)
 |-
 | 0x13 || set backlight. Temporary.
@@ Line 41: / Line 41: @@
 | 0x14 || reinit LCD.  The initialzation procedure of the LCD takes a long time. A timed delay of about 500ms is in order after issuing this command.
 |-
-| 0x17 || set backlight, save to EEPROM.
+| 0x17 || set backlight, save to EEPROM. (*)
 |-
-| 0x20 || set the number of lines. Should not be necessary in most circumstances.
+| 0x20 || set the number of lines. Should not be necessary in most circumstances. (*)
 |-
-| 0x21 || set the number of characters per line. Should not be necessary in most circumstances.
+| 0x21 || set the number of characters per line. Should not be necessary in most circumstances. (*)
 |-
-| 0xf0 || change address. Requires a write to 0xf1 and 0xf2 first.
+| 0xf0 || change address. Requires a write to 0xf1 and 0xf2 first. (*)
 |-
 | 0xf1 || write 0x55 here to start unlocking the change address register.
@@ Line 53: / Line 53: @@
 | 0xf2 || write 0xaa here to unlock the change address register.
 |}
+(*) These values are written to the eeprom. If you write "0xff", the value will be interpreted as "empty eeprom" on next boot, and the default will be used.
 = read ports =

@@ Line 39: / Line 39: @@
 | 0x13 || set backlight. Temporary.
 |-
+| 0x14 || reinit LCD.  The initialzation procedure of the LCD takes a long time. A timed delay of about 500ms is in order after issuing this command.
-| 0x14 || reinit LCD.
 |-
 | 0x17 || set backlight, save to EEPROM.

@@ Line 51: / Line 51: @@
 | 0xf1 || write 0x55 here to start unlocking the change address register.
 |-
-| 0xf0 || write 0xaa here to unlock the change address register.
+| 0xf2 || write 0xaa here to unlock the change address register.
 |}

@@ Line 55: / Line 55: @@
 = read ports =
-The spi_lcd board supports two read ports:
+The lcd boards support several read ports:
 {| border=1
@@ Line 63: / Line 63: @@
 |-
 | 0x02 || read eeprom (serial number).
+|-
+| 0x12 || current contrast value.
+|-
+| 0x13 || current backlight value.
+|-
+| 0x16 || number of bytes-in-buffer. The buffer is 32 bytes, This allows you to prevent sending a long string if it will overrun the buffer.
+|-
+| 0x17 || read the power-up-backlight-value (not the current).
 |}
 = startup message =

@@ Line 33: / Line 33: @@
 | 0x10 || any data clears the screen.
 |-
-| 0x11 || move the cursor to line l, position p. <br>l is the top 3 bits<br>p is the bottom 5 bits of the data. Both are zero-based. The top line is line 0, the left character is char 0.
+| 0x11 || move the cursor to line l, position p. <br>l is the top 3 bits<br>p is the bottom 5 bits of the data.<br>Both are zero-based. The top line is line 0, the left character is char 0.
 |-
 | 0x12 || set contrast.