Holtek IR Codes

General JP1 chit-chat. Developing special protocols, decoding IR signals, etc. Also a place to discuss Tips, Tricks, and How-To's.

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JPannell
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Joined: Thu Apr 29, 2004 7:44 pm

Holtek IR Codes

Post by JPannell »

Hi All,
I have built a IR transmitter/receiver to control a few devices that did not normally have IR control. My 15-1994 will learn the signals and transmit them properly, but when I go to develop a new device using these commands I have trouble analyzing the learned signals for keymap master. I have uploaded my IR file to the yahoo group(Holtek.txt) The remote/receiver uses a holtek HT-12A/D chip pair. I would like to be able to make a device/protocol for this so that I am able to use an extended(no longer learning) 9910 remote. Any tips on what to do next?

Holtek.txt

Thanks,
Jason
johnsfine
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Post by johnsfine »

To make a good estimate of which of the 12 bits are device vs. command vs check bits, we probably need to see a wider range of signals.

This protocol has demonstrated a bug in my generic decoder for phase encoded protocols. It is not a phase encoded protocol and the simple rules that I thought I coded for distinguishing phase encoded protocols should reject it, yet it is reported as phase encoded.

It is a very simple protocol: 12 bits of a simple burst per bit. Unfortunately, the bursts are backwards compared to the usual conventions for IR signalling. Each burst is an Off then On, rather than the usual On then Off.

The basic design for IR signal generation in the UEI remotes is based on either On/Off bursts or phase encoding. There is no direct support for Off/On bursts.

The crude solution is to simplify the bit definition to be one third of a true bit, so you transmit 36 "bits" of a form it knows how to do instead 12 bits of a form it doesn't.

That in turn can be done easily by having the tripled data in the upgrade computed by a protocols.ini entry in RM. But that makes for a much larger device upgrade than it ought to be. With more difficulty, the tripling can be done in S3C80 asm code hand inserted into the protocol upgrade.

There are also a few other ways to generate signals that don't fit the standard On/Off pattern. I haven't done one in long enough I forget a bunch of key details for each such method.

I expect Jon and/or Rob will comment and/or take over.
JPannell
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Post by JPannell »

Hi John,
The device has 8 adress bits and 4 data bits. The address bits are all grounded. Right now I only have four switches hooked up, as that is all I needed, but I could try to rig some more switches up if needed. Right now I pull one of the data bits low for each of the buttons so the dat transmitted would be 3 high and one low for each switch. The data sheet for the device is here.
http://www.holtek.com.tw/pdf/consumer/2_12ev110.pdf
jon_armstrong
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Post by jon_armstrong »

Here is a zip file containing three files one used with KM Master, Protocol Builder, and an IR file that you can load straight into your 1994 to test. It is on the cable device and numerals 1 through 4.

This is based on John Fine's explanation above of the "crude method" since it only has four commands it should work OK.

Here are the device and protocol upgrades for a 1994:

Upgrade Code 0 = 0F C6 (Cable/1990)
88 00 81 DB 6D B6 00 00 49 60 4B 20 59 20 C9 20
00 00 00 00 00 00 00 00 00 00
End

Upgrade Protocol 0 = 01 88 (S3C8)
3D 92 32 8B 15 8B 05 08 08 00 D2 00 00 00 00 00
BE 1B F5 00 D2 00 BE FF FF 04 8D 01 33
End
-Jon
JPannell
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Post by JPannell »

Thanks Jon,
I am at work right now, but I will test it when I get home.
Thanks,
Jason
JPannell
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Post by JPannell »

I tried the upgrade protocol and device, and it works perfectly. Thank you John and Jon.
Jason
jon_armstrong
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Post by jon_armstrong »

I'm glad it worked. The commands I used are known as double byte commands since the variable portion takes two bytes. If you wnat to key move them, they must be done using IR and select the radio button "hex" and put both bytes with one space in between. Those bytes, including the space, are in the OBC column of the KM Master.

If you think you are going to want more commands, I can send you my spreadsheet where I decoded the learned commands. Or, explain the simple method of encoding if it is not obvious to you.
-Jon
JPannell
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Post by JPannell »

Hi Jon,
I would be interested in the spreadsheet, my address is:
jpannell at shaw.ca
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