|The protocol is from the NEC infra-red RC5 standard.|
1) It is based on sending a byte, call it A, for the type of equipment (the vendor and model code)
2) The logical inverse, ~A
3) Then a byte for the key pressed, call it B.
4) Then the logical inverse of this ~B.
Altogether the code will be be of the form: A,~A,B,~B
The start pulse, timing and repeat key signals are all typical for the standard.
The key pressed codes are allocated by the position on the pad.
The LABELS on the typical pad follow this pattern:
1 2 3
4 5 6
AUTOSET RESTORE LOCK
???? POS FILTER
NORMAL GENLOCK PIP
LEFT PAN RIGHT
ZOOM SHRINK FREEZE
For some features AUTOSET is replaced with label 7, RESTORE with 8 and LOCK with 9.
For these positions the following codes are allocated (shown in hex):
0x15 0x17 0x0E
0x00 0x01 0x02
0x03 0x04 0x05
0x06 0x07 0x08
0x11 0x09 0x16
0x0D 0x19 0x0C
0x13 0x10 0x1A
The vendor/model code is 0x10.
The data is sent least significant bit of byte first.
So for the key laebelled STORE with a code of 0x1F (decimal 31), the information sent will be:
0x10 0xEF 0x1F 0xE0 (binary is 00010000 11101111 00011111 11100000)
ID is 0x10
Key table is:
LABEL HEX CODE