path: root/Documentation/arm/empeg/ir.txt

Infra-red driver documentation.

Mike Crowe <mac@empeg.com>
(C) Empeg Ltd 1999

Not a lot here yet :-)

The Kenwood KCA-R6A remote control generates a sequence like the following:

Go low for approx 16T (Around 9000us)
Go high for approx 8T (Around 4000us)
Go low for less than 2T (Around 750us)

For each of the 32 bits
  Go high for more than 2T (Around 1500us) == 1
  Go high for less than T (Around 400us) == 0
  Go low for less than 2T (Around 750us)

Rather than repeat a signal when the button is held down certain buttons
generate the following code to indicate repetition.

Go low for approx 16T
Go high for approx 4T
Go low for less than 2T

(By removing the <2T from the start of the sequence and placing at the end
 it can be considered a stop bit but I found it easier to deal with it at
 the start).

The 32 bits are encoded as XxYy where x and y are the actual data values
while X and Y are the logical inverses of the associated data values. Using 
LSB first yields sensible codes for the numbers.

All codes are of the form b9xx

The numeric keys generate the code 0x where x is the number pressed.

Tuner		1c
Tape		1d
CD		1e
CD-MD-CH	1f
Track-		0a
Track+		0b
Rewind		0c
FF		0d
DNPP		5e
Play/Pause	0e
Vol+		14
Vol-		15