help calculating word hex code from OBC value of IR signal

[longpole001]

looking again at your example , how would a shift be done in the basic code , i have included a summery sheet of the codes for ref , it seem each OBC 0 - 15 . 16 - 31, etc code x0 xF changes on each 16 OBC codes group

since each OBC code is different for each remote using the same function , yes i have to allow for 3 remotes that look similar , do the same function over all , but are sending different codes for the same function , i thought that having only the OBC for each remote key would save a lot of storage space on the prom.

NEC1 - IR Remote Code table Reference

SigKey #	Button key FUNCTION Reference	Red to White 16 or 20 steps	Remote 1			Remote 2			Remote 3
			OBC	HEX	Full Hex Code	OBC	HEX	Full Hex Code	OBC	HEX	Full Hex Code
1	Brightness UP		5	5F	00 FF A0 5F	0	FF	00 F7 00 FF	92	C5	00 FF 3A C5
2	Brightness DWN		4	DF	00 FF 20 DF	1	7F	00 F7 80 7F	93	45	00 FF BA 45
3	PWR Off		6	9F	00 FF 60 9F	2	BF	00 F7 40 BF	65	7D	00 FF 82 7D
4	PWR On		7	1F	00 FF E0 1F	3	3F	00 F7 C0 3F	64	FD	00 FF 02 FD
5	RED	1	9	6F	00 FF 90 6F	4	DF	00 F7 20 DF	88	E5	00 FF 1A E5
6	GREEN	6	8	EF	00 FF 10 EF	5	5F	00 F7 A0 5F	89	65	00 FF 9A 65
7	BLUE	11	10	AF	00 FF 50 AF	6	9F	00 F7 60 9F	69	5D	00 FF A2 5D
8	WHITE	16 (20)	11	2F	00 FF D0 2F	7	1F	00 F7 E0 1F	68	DD	00 FF 22 DD
9	Button 1	2	13	4F	00 FF B0 4F	8	EF	00 F7 10 EF	84	D5	00 FF 2A D5
10	Button 2	7	12	CF	00 FF 30 CF	9	6F	00 F7 90 6F	85	55	00 FF AA 55
11	Button 3	12	14	8F	00 FF 70 8F	10	AF	00 F7 50 AF	73	6D	00 FF 92 6D
12	Button 4	Flash(19)	15	0F	00 FF F0 0F	11	2F	00 F7 D0 2F	72	ED	00 FF 12 ED
13	Button 5	3	21	57	00 FF A8 57	12	CF	00 F7 30 CF	80	F5	00 FF 0A F5
14	Button 6	8	20	D7	00 FF 28 D7	13	4F	00 F7 B0 4F	81	75	00 FF 8A 75
15	Button 7	13	22	97	00 FF 68 97	14	8F	00 F7 70 8F	77	4D	00 FF B2 4D
16	Button 8	Strobe (18)	23	17	00 FF E8 17	15	0F	00 F7 F0 0F	76	CD	00 FF 32 CD
17	Button 9	4	25	67	00 FF 98 67	16	F7	00 F7 08 F7	28	C7	00 FF 38 C7
18	Button 10	9	24	E7	00 FF 18 E7	17	77	00 F7 88 77	29	47	00 FF B8 47
19	Button 11	14	26	A7	00 FF 58 A7	18	B7	00 F7 48 B7	30	87	00 FF 78 87
20	Button 12	Fade (17)	27	27	00 FF D8 27	19	37	00 F7 C8 37	31	07	00 FF F8 07
21	Button 13	5	17	77	00 FF 88 77	20	D7	00 F7 28 D7	24	E7	00 FF 18 E7
22	Button 14	10	16	F7	00 FF 08 F7	21	57	00 F7 A8 57	25	67	00 FF 98 67
23	Button 15	15	18	B7	00 FF 48 B7	22	97	00 F7 68 97	26	A7	00 FF 58 A7
24	Button 16	Smooth (16)	19	37	00 FF C8 37	23	17	00 F7 E8 17	27	27	00 FF D8 27
25	Button 17	Red Up							20	D7	00 FF 28 D7
26	Button 18	Green Up							21	57	00 FF A8 57
27	Button 19	Blue up							22	97	00 FF 68 97
28	Button 20	Quick							23	17	00 FF E8 17
29	Button 21	Red Dwn							16	F7	00 FF 08 F7
30	Button 22	Green Dwn							17	77	00 FF 88 77
31	Button 23	Blue Dwn							18	B7	00 FF 48 B7
32	Button 24	Slow							19	37	00 FF C8 37
33	Button 25	DIY1							12	CF	00 FF 30 CF
34	Button 26	DIY2							13	4F	00 FF B0 4F
35	Button 27	DIY3							14	8F	00 FF 70 8F
36	Button 28	Auto							15	0F	00 FF F0 0F
37	Button 29	DIY4							8	EF	00 FF 10 EF
38	Button 30	DIY5							9	6F	00 FF 90 6F
39	Button 31	DIY6							10	AF	00 FF 50 AF
40	Button 32	Flash							11	2F	00 FF D0 2F
41	Button 33	Jump 3							4	DF	00 FF 20 DF
42	Button 34	Jump 7							5	5F	00 FF A0 5F
43	Button 35	Fade3							6	9F	00 FF 60 9F
44	Button 36	Fade7							7	1F	00 FF E0 1F

[Jerson]

34	Button 26	DIY2							13	4F	00 FF B0 4F
35	Button 27	DIY3							14	8F	00 FF 70 8F

First of all, I don't know what is OBC. Please expand abbreviations the first time around.

Taking just these 2 examples, it seems pretty intuitive to me.

Let us take the case of Sigkey#34 button 26. The code you see is 00 FF B0 4F
The first byte 00 must be some kind of device ID or something.
The second byte is just the binary inverse (NOT operation) of the first byte
The third byte is the function code
and the 4th byte is the inverted function code. Just like the second byte.

The easiest way to do this is to have a lookup table having the codes for bytes 1 and 3 and you generate the bytes 2 and 4 before sending them out.

It's that easy