UART<->3LB

This feature allows other devices (e.g. a CarPC or a smartphone) to display text or graphics on the screen of the instrument cluster. The FIS-Control acts as a converter between a serial interface (RS-232 or bluetooth) and the 3-wire-bus of the cluster.


To quit this mode, perform a longpress on the set-button.

The baudrate is 115200. Every command starts with one byte that indicates how many bytes are following. The next byte selects the function:
0x00: Release the display (the normal board computer will be shown again)
0x01: Initialize the display (only the upper two lines)
0x02: Initialize the display (like a satnav would do it)
0x03: Write text to the upper to lines of the screen
0x04: Write text or symbols to the middle segment of the screen
0x05: Clear one complete line of the middle segment
0x06: Draw graphics. As payload-length 0xFF should be sent, even though the payload actually has to be 384 bytes long. Every byte is for 8 pixels. Therefore every line of the screen will take 8 bytes. That gives 384 bytes for the complete screen with 48 rows.

The commands 00, 01 and 02 don't need any more parameters.

The command 03 expects up to 16 characters of text that shall be displayed in the upper segment of the screen.
The commands don't need to be terminated with a carriage return or line feed character.

The command 04 has 3 parameter bytes.
The first on chooses the font:
0x00: Big font with background color, left-aligned
0x01: Big font inverse to background, left-aligned
0x02: Big font without background color, left-aligned
0x04: Small font with background color, left-aligned
0x05: Small font inverse to background, left-aligned
0x06: Small font without background color, left-aligned
0x20: Big font with background color, center
0x21: Big font inverse to background, center

0x22: Big font without background, center
0x24: Small font with background color, center
0x25: Small font inverse to background, center

0x26: Small font without background, center
0x0A: Several satnav symbols

The second and third parameter byte gives the X- / Y-position of the text.

Now the text or the coed of the satnav symbols are following.

The command 05 expects one parameter. The row of the text that shall be cleared completely.


Examples:
To print a "HELLO!" in the middle segment you have to send the following:
Initialize the screen:
0x01 0x02 -> payload is one byte, selected command is 0x02

Write text:
0x0A 0x04 0x26 0x00 0x10 0x48 0x45 0x4C 0x4C 0x4F 0x21 -> payload is 10 Bytes, function 4, font 0x26, x-position 0, y-position 16 and then the ASCII characters for HELLO!


A typical output of a satnav could look like this:
01 02 -> Init screen
0B 04 0A 0B 15 74 74 74 74 4F 50 74
0B 04 0A 0B 1C 74 74 74 74 67 5A 74
09 04 0A 11 23 74 74 74 64 5F
08 04 06 18 12 5A 49 45 4C
08 04 06 01 1D 4F 46 46 20
09 04 06 01 27 52 4F 41 44 20
07 04 06 01 01 35 34 35
06 04 06 01 0B 4B 4D

Every command is acknowledged by the FIS-Control with one byte. On success it is the character '0', else you will receive a error code, e.g. '1' when an unknown command was received.

If the user presses a button on the wiper stalk, the FIS-Control will send a corresponding byte to the connected device:
'u': up-key
'U': longpress on up-key
'd': down-key
'D': longpress on down-key
's': set-key