Hello,

Can anybody explain the details for the Sharp IR code format, specifically as it applies to the Denon receivers?

I was able to come up to speed on some of the specifics of IR codes from Barry Gordon's FAQ and documentation for GenIRDB (Thanks for the great discussion Barry!). However, I have some confusion with respect to the Non-repeating and repeating burst sequences in the Sharp IR and/or Pronto HEX format.

As an example of my confusion, I have downloaded the AVR3802 RC Code documentation from the Denon Website. It gives details for all of the commands and from what I can tell, the "Power On" command would consist of a "non-repeating" codeword: 01000 100001 11 00. Here, the first field (System Address) is "01000", the second field (Function) is "100001" and the other two fields seem to be fixed. I believe this would yeild the Pronto HEX equivalent command for entry as a learned IR code as follows:

0000 006D 0010 0000 000A 001E 000A 0046 000A 001E 000A 001E 000A 001E 000A 0046 000A 001E 000A 001E 000A 001E 000A 001E 000A 0046 000A 0046 000A 0046 000A 001E 000A 001E 000A 06D6

However, as a check to see if I constructed the code correctly (by looking at the Denon Receiver Discrete Codes on this website ([Link: remotecentral.com])

It seems to list both a "non-repeating" burst sequence (similar to the one I constructed above), followed by a 2-command repeating burst sequence (listed below in Denon's binary command format, in order to be concise):
01000 100001 11 00
01000 011110 00 11

This to me looks like a function called "Panel" in the Denon documentation, followed by the inverse of the Panel function (although the "System Address" field is not inverted).

To confuse me even more, I downloaded Tyler Ager's PCF file which contains learned codes for the AVR-3802 (Thanks Tyler!) at : [Link: remotecentral.com]

Looking at his PCF file, it appears that the learned IR code doesn't contain any "non-repeating" sequence, but contains a 2-command "repeating" sequence:
01000 100001 11 00 (Power-on command)
01000 011110 00 11 (Inverted Power-On Command).

I have also seen similar codes on this forum (like the thread relating to the Video Select function on the AVR-3801), which has the same command repeated 4 times (twice non-inverted, twice inverted ... interlaced):
01000 000110 11 00 ("Video Select" Function)
01000 111001 00 11 (Inverted "Video Select" Function)
01000 000110 11 00 ("Video Select" Function)
01000 111001 00 11 (Inverted "Video Select" Function)

So my questions are:
1) Is there any method to this madness, or are these IR codes pretty flexible (like the "Panel" command repeating after a "Power-on" command being innocuous) and can be constructed any number of ways?
2) Do you get enhanced reliability by repeating codes?
3) Does the Sharp format (or at least as it pertains to the Denon equipment) require repeating patterns to be inverted?
4) If the Sharp format requires repeating sequences to have an inversion on the second command, how come the "System Address" field is not inverted?

Thanks in advance to any help anyone can offer. I'd like to understand the structure of these codes better for my own customization needs. I hope this will also help me determine wether my learned commands look correct to me ... as a sanity check for debugging purposes.

- Confused

There is no non-repeating part in the Sharp IR protocol.


I probably read that document long ago, but I can't find it now. A URL would help. Your post doesn't make clear which document you mean. Does it really say "non-repeating"?


Denon documents the function field as 6 bits and documents the 2 bits after the function field as something else, but those 2 bits are not fixed and they act for all practical purposes as part of the function field. So those of us who have reverse engineered various IR protocols, treat the function field in Denon as 8 bits.


My enhanced copy of the IrTool program decodes that as a non-repeating first half of a Denon signal, device 2, command 225.
Device 2 in binary backwards is 01000, which matches what you said.
Command 225 in binary backwards is 10000111, which could match what you said depending on what you wanted the last two bits to be.


That whole signal is first-half non-repeating, followed by second and first halves repeating, so it will correctly start with the first half and correctly repeat alternating the two halves, but will end with the first half. I doubt that it matters which half you end with. If it matters, I suspect it's better to end with the second half, but I'm not sure there isn't some good reason for ending with the first half.


This is a standard part of the Sharp/Denon protocol. Every command has two of what I've been calling "halves", where the second half has the same System Address and inverts all other bits.


That's the "correct" Denon protocol as most of the experts here understand it.


There is method to the madness. I think I made it clear above. But the device receiving the signal probably isn't very picky about the pattern of the two halves that it sees.


Actual Sharp and Denon remotes send the alternating pattern I described. I have no guess what the Denon device might do if it received a repeat sequence that didn't alternate.


That's just the way they designed it.

John,

Thanks for the reply. You've cleared some things up for me. BTW, the Denon document I was referring to is located at: [Link: usa.denon.com]

It doesn't explicitly say that the Power-On/Off codes were non-repeating ... that was just my own assumption. At the risk of showing my ignorance (yep, I got lots of it ... LOL), I thought that non-repeating code types were for single commands (like a power command, input select command) and repeating code types were for functions that would keep repeating if you continue to hold down a particular button (like a Volume+ command) ... is this wrong thinking?

I suppose that if the Sharp IR protocol doesn't use any non-repeating code types, the Pronto HEX format would always look something like this:
0000 006D 0000 0020 ... (followed by the encoding for the 32-bit command, along with the lead-out sequence at the appropriate times)
Where the 3rd HEX value "0000" represents a zero-length non-repeating code and the 4th hex value represents a 32-bit long repeating code.
If I understand correctly now, it seems as though all Denon codes are considered repeating, with the first "half" (16-bits) being the Device/function pair listed in the table from the Denon website, and the second "half" being the same Device code, but having inverted function (& extension) bits. Does this sound correct?

Also, it looks like you were right about the 8-bit "Function" field (instead of 6). I just mis-understood the table in the Denon documentation.

Anyway, thanks for the feedback - I think I'm starting to get it.

- Pfliegster

Specific functions do have repeating or non-repeating behavior as you describe. But very few devices use any difference in IR signaling between repeating and non-repeating functions. The difference is not in what the remote sends when you hold the key down. The difference is in how the device responds to that held signal.

Typically, the non-repeating part of the Pronto Hex is for protocols that have special lead-in on the first copy of the command, or protocols that repeat a special "still pressed" signal that is totally different from the initial press signal. There are protocols that don't repeat at all. There are also a few that do what you seem to have assumed would be normal (repeat or not based on the type of command), but those are a small minority that doesn't include Denon.


All correct, except that you didn't mention the last two bits (the two after the extension bits). There are four possible values for those two bits:
00 = First half of a Denon signal
10 = First half of a Sharp signal
01 = Second half of a Sharp signal
11 = Second half of a Denon signal

So the last bit always tells you which half this is. The second half has the same first 5 bits and the inverted last 10 bits from the first half. The second to last bit tells Sharp vs. Denon (subject to being inverted in the second half).

Ahhhhh .... Finally, I'm starting to see the method behind the madness. Thanks for the good explanation.

BTW: Do you know of any place where all of the IR formats (Sharp, Denon, NEC, Sony ...) are documented in excruciating detail (including details of repeating/non-repeating, structure of first half/second half, Lead-in's, etc.)? Or have most companies tried to keep these formats proprietary ... making the Home Theatre enthusiasts reverse-engineer these codes?

Also - I'm pretty psyched that Denon has published these code tables, however I've had no luck finding detailed function tables for some of my other components (like my Sony TV). Do you know of a repository of all of this information (aside from digging through other peoples' PCFs & CCFs on this excellent site)?

For instance, I've been able to learn all of the keys on my TV remote into the Pronto ... except for 1 (the "TV" button). This button works as expected from the factory remote, but I've tried several times unsuccessfully to learn it with Pronto. Pronto thinks that it learned it (giving the affirmative beep), but when I press the button ... nothing happens. If I had the function tables for this particular TV, I could compare one of my other learned codes that works to the table and then try to analyze the code that Pronto incorrectly learned ... and edit it to correct any error I find.

Thanks again for the help.

The TV code can be found in the discretes section. The ANT button is more tricky since it toggles between ANT and AUX. The TV button in the discretes will get you to ANT I believe, but there isn't a reliable way to get to AUX.

I think this is what you were referring to.

Jon

Jon,

Thanks. The "Tuner" discrete seemed to do the trick for me.

It would still be good to be able to find a good table documenting these Sony TV codes - even though most of my other "learned" codes seem to work OK, it looks like several of them (not available in the "discrete" list) are real long codes (probably because I held the button too long?). I'd like to go through and clean these up at some point, but it would be nice if I had some documentation to do it by ... not trial & error.

Anyway, thanks. I'm up and running now.

Pfliegster,

Not sure if you've looked here [Link: anycities.com]

I haven't really looked at it but I've seen this link in other posts where people were asking about sony codes. Hope it helps you.

Jon