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Looking codes for Hitachi FX-77

 
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mario



Joined: 14 Oct 2003
Posts: 5

PostPosted: Tue Oct 14, 2003 8:03 pm    Post subject: Looking codes for Hitachi FX-77 Reply with quote

I'm looking for the codes to program my OFA remote. Unfortunately, I don't have a learning remote (Got the URC-6017, that can be made JP1 Compatible).

I would be more than happy I someone found a way to control the Power and Volume from the HITACHI FX-77 Audio Receiver, CD, Tape combo.

The only info found to date is related to LIRC...
http://mars.wiwi.uni-halle.de/lirc/remotes/hitachi/RB-77
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johnsfine
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Joined: 10 Aug 2003
Posts: 4766
Location: Bedford, MA

PostPosted: Tue Oct 14, 2003 10:01 pm    Post subject: Reply with quote

That LIRC data is a rather distorted description of the NEC1 protocol. I'm fairly sure Hitachi uses ordinary NEC1, so I'll assume none of the significant distortions need to be reproduced.

I never remember exactly how to read LIRC data. I usually apply what I already know about the signals to what the LIRC data provides in order to deduce the details. In this case things don't add up very well, so I'm not sure I'm reading it right.

I'm nearly certain they have the bits inverted (consistent with their inverted definition of "one" and "zero"). I'm quite sure their 16 pre_data_bits are the device info. I'm quite sure their 1 post_data_bits are just the last bit which just happens not to change in any of these signals, which is why they have only 15 data bits instead of 16 and why the actual values are obviously shifted by one bit position.

What I'm not sure about is the bit sequence. I think they go high to low within the 16 pre data bits and high to low within the 15 variable bits. So the device "DA" reversed and inverted is 01010100 binary, which is device 164.

Continuing that point of view, power is OBC 255, vl+ is OBC 254, vl- is OBC 253, etc.

I can't find any UEI setup code nor any data at RC nor other places that matches this. The pattern of OBC numbers feels wrong, so it feels like I'm misinterpreting some aspect of that LIRC data, but I can't see a better interpretation.

I'm pretty sure there's no support for this without JP1. With JP1, there's just a few conceivable ways to interpret that LIRC data and each is easy to test. You can start with what I put above. If those are right someone can tell you the rest of the OBCs. If they're wrong, someone can tell you a better (or at least different) way to interpret that LIRC data.
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uwereinert
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Joined: 27 Aug 2003
Posts: 153
Location: Chemnitz

PostPosted: Wed Oct 15, 2003 1:20 am    Post subject: Reply with quote

johnsfine wrote:
Continuing that point of view, power is OBC 255

That's ok, but vol+ is OBC 253 and vol- is OBC 251. The third and the fourth digit from the right side of the LIRC datas are the hex commands. To translate them into EFC's, you could use the EFC calculator from IR, e.g., Power = EFC 018, Vol+ = EFC 016, Vol- = EFC 019, Menu = EFC 115 and so on.

Uwe
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johnsfine
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Joined: 10 Aug 2003
Posts: 4766
Location: Bedford, MA

PostPosted: Wed Oct 15, 2003 5:42 am    Post subject: Reply with quote

uwereinert wrote:

That's ok, but vol+ is OBC 253 and vol- is OBC 251. The third and the fourth digit from the right side of the LIRC datas are the hex commands. To translate them into EFC's, you could use the EFC calculator from IR, e.g., Power = EFC 018, Vol+ = EFC 016, Vol- = EFC 019, Menu = EFC 115 and so on.


NEC1 in LIRC with reversed 0's and 1's would work that way if they hadn't also shifted everything over by one bit.

In this case the bottom 7 bits followed by an extra bit of zero act as you describe, but that fact isn't very helpful to someone who doesn't do hex math in their head quickly.
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mario



Joined: 14 Oct 2003
Posts: 5

PostPosted: Thu Oct 16, 2003 9:47 pm    Post subject: Reply with quote

That's a lot of new infos for me... but I might have mixed all things up...

Today I manage to recapture the IR codes using a UIR device that translate the IR stream into an HEX string.

Captured examples:

DA 25 00 FF -->POWER
DA 25 40 BF -->VL-
DA 25 80 7F -->VL+

From the POWER button and your explanation, this is what I understand:

Protocol is indeed NEC1
DA is converted to Device Number 164
25 would be Sub Device 91?
00 is EFC 18
And where should I use the FF part?

I am using RemoteMaster to create the "Upgrade device" string.
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uwereinert
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Joined: 27 Aug 2003
Posts: 153
Location: Chemnitz

PostPosted: Fri Oct 17, 2003 12:46 am    Post subject: Reply with quote

mario wrote:
25 would be Sub Device 91?

Right, but it is the comp value to 164 too, therefor you can use NEC1:164 (00 DA DA) or NEC1:164:91 (20 DA 25), the generated IR is the same.

mario wrote:
And where should I use the FF part?

Nowhere, you don't need the last two digits of the LIRC datas.

Uwe
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johnsfine
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Joined: 10 Aug 2003
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PostPosted: Fri Oct 17, 2003 6:11 am    Post subject: Reply with quote

mario wrote:
DA is converted to Device Number 164


Yes, but you'll notice that DA hex is not 164 decimal. The bits were inverted and reversed to get the right value. If you put DA in the hex command field of IR's EFC calculator, 164 shows up in the LSB Comp field, which is the required transformation.

mario wrote:
25 would be Sub Device 91?


No. 25+DA = FF, which fits the special rule for no sub device, so subdevice in RM shoulb be kept blank.

mario wrote:
00 is EFC 18
And where should I use the FF part?


00 is the hex command. The FF is redundant and you can ignore it.
Note this third byte is transformed the same way to get OBC as the first byte is transformed to get device, but RM does that for you (no reason to use the EFC calculator).
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mario



Joined: 14 Oct 2003
Posts: 5

PostPosted: Fri Oct 17, 2003 9:32 pm    Post subject: Reply with quote

Yup! that was right,

Thanks for your help, I finally managed to add this remote under a new device code. As soon as it is complete, I'll make it available on the Jp1 yahoo group.
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