NICAM sound

I am looking at building a NICAM decoder for the Philips/Sony SA tivos to use in New Zealand, similar to the "Mark 1 stereo decoder" used in Australia. The tivo will need to have a PAL tuner fitted along with this additional circuit - see TunerModALPSHowTo for details of the fitting a tuner and how the "Mark 1" stereo mod is used in Aussie.

Also see NzStereoSupport for details on why we cant get NICAM sound on the Philips/Sony tivos.

The cost of the required components is estimated to be about NZ$35-40, and will use the STV8216D

Since the minimum order quantity for this part is 25 units (and I don't own that many tivos!), is anyone else interested in performing this modification before I commit? All suggestions welcome! :)

Why not use a second MSP chip instead as per http://forums.oztivo.net/showpost.ph...8&postcount=10 ?

Effectively that is what I am doing, but the default reset settings of the ST part should decode the NICAM without having to program the chip each time the tivo boots. I agree that a second Micronas chip would work too, but I see it as more work as it requires software to configure it over I2C?

Sounds good. I've previously resisted putting in a pal tuner as I don't want to go without stereo sound. I'm currently using an external nicam video with the ir blaster control, which works well except for the occasional missed change of channel, and the delay, but an internal pal tuner which captures stereo would be much better.

I'll do the PCB for you if you like, unless you can do that yourself? Depending on the size of the board, they will be about US$4 each.
I'll have a board and so will a friend of mine. Other people I know with TiVos probably don't care.

I have managed to source the ICs from a contact in Taiwan who had 5 in stock rather than using NZ distributors, allowing me to make sure a prototype works as expected before buying in lots of 25. I'll update here when I have received and tested it.

Skolink: Thanks for the offer but I can make a plain single sided PCB which will be fine for the prototype.

Hiya.

I'll be in for one if you can supply chip and circuit board. Any idea on where to get PAL tuners from? Are you able to supply chip, circuit board and Tuner?

Darren is the man for tuners: http://www.kingey1971.com/tivo/index.htm

Sorry for the delay on updates - schematic now attached!

I ran into an issue that the default settings for the STV8216 were all fine - except the outputs are muted on startup! The tivo I2C bus *should* have been capable of turning the mute off, but for some unknown reason it refuses to communicate with devices at normally unused addresses. I now have a PIC micro which turns the mute off instead, which is a simple workaround for the problem.

The prototype has been running for a month or two now without any issues and sounds much better/clearer than the mono sound from the tuner. :)

The circuit is shown in the photo to give an idea of what is required to build your own, it's a bit rough, but remember that it is a prototype (and it works)!

Glad to hear that the nicam problem has been solved.

Do you have the pcb design available to create a pcb with?
Pity about the tivo not letting you communicate with the decoder chip, nice workaround though.

Do you have the decoder chips available to purchase yet, or are the ones you've got so far taken?

That's a nice bit of hardware. Great job!

I'll link this thread from my website as the source of information for the PAL tuner with NICAM decoding solution discussion area.

I am assuming that the hook up will be very similar to the old "Mark 1" Australian stereo decoder and if some pictures and info can be sent to me I'll happily update the how-to to incorporate the changes, or I'm happy for someone to use the current how-to and re-write it.

As for myself I unfortunately can't be in a position of active participation due to Australia not using NICAM so someone in NZ will have to take on the role of answering technical questions.

While I realise this decoder and a different PIC chip can program it for use in Australia I have enough stock of 3410D Micronas chips to last out the remainder of any future conversions that come my way. Although if Catdog wants to develop an Australian version (or a universal version that can do many standards) then go for your life mate :D

Once again, great work. Well done :)

Quote:

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Originally Posted by Darren King

I am assuming that the hook up will be very similar to the old "Mark 1" Australian stereo decoder and if some pictures and info can be sent to me I'll happily update the how-to to incorporate the changes, or I'm happy for someone to use the current how-to and re-write it.

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Yes, exactly the same although it requires both 12V and 5V.

Quote:

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Originally Posted by Darren King

Although if Catdog wants to develop an Australian version (or a universal version that can do many standards) then go for your life mate :D

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One step ahead of you - it autodetects the sound standard so should work in Australia as is!

I have installed one of these decoders in my Tivo, and can say it works really well. After putting in the pal turner and using the demodulated (mono) sound from the tuner, I thought that the sound was pretty good. Putting in the NICAM decoder and listing to it, the sound is so much better…

The decoder performs flawlessly. Locking onto the NICAM signal occurs virtually instantly. There is no noise output while changing channels, and the decoder falls back automatically to mono if the station does not broadcast in NICAM.

Very happy with the decoder.

Hi. I live in Wellington, and have previously had a PAL tuner installed in my Tivo.
I'm quite keen on getting Nicam stereo working. What's the easiest way, and what would the costs be?
Ta.

If Catdog doesn't have any prototype boards left, you may want to wait until I build some 'pretty' NICAM decoder boards.
It will likely take a couple of months by the time I lay out the PCB, and then slip some PCBs in with a work job for fabrication, then assemble the boards.
Not sure of costs, have yet to look into component sourcing - NZ$ is high vs US$ which should help.

I have installed one of Catdog's prototype NICAM decoders, but I now have no audio from the tuner. Could this be because this TiVo has a 'MKII stereo' mod where the MSP3430G is replaced by a MSP3430D? I assume that the MSP3430D is trying to decode the tuner SIF rather than using the audio coming in on pins 56 and 57. Is there some way to override this automatic setting?
I have removed Q14 and L28 (the opposite of upgrading a MKI stereo mod to a MKII).

Quote:

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Originally Posted by Skolink

I have installed one of Catdog's prototype NICAM decoders, but I now have no audio from the tuner. Could this be because this TiVo has a 'MKII stereo' mod where the MSP3430G is replaced by a MSP3430D? I assume that the MSP3430D is trying to decode the tuner SIF rather than using the audio coming in on pins 56 and 57. Is there some way to override this automatic setting?
I have removed Q14 and L28 (the opposite of upgrading a MKI stereo mod to a MKII).

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Briefly looking at the Palmod source code:

Code:

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        // Setup for tuner input
        if (mspType == MSP3410D) {
                iicw4(MSP_CHIP, WRITE_DEMOD, MODE | 0x8018);                                        // set device to slave mode
                iicw4(MSP_CHIP, WRITE_DEMOD, STANDARD_SELECT | AUTO_DETECT);        // autodetect sound standard
                //iicw4(MSP_CHIP, WRITE_DEMOD, AUTO_FM | 0x0001);                                // use error rate to determine sound
                iicw4(MSP_CHIP, WRITE_DEMOD, AUTO_FM | 0x0800);                                // select AM/FM sound
                iicw4(MSP_CHIP, WRITE_DEMOD, AD_CV | 0x00d0);                                        // set automatic gain control
                iicw4(MSP_CHIP, WRITE_DSP, I2S_SOURCE_MODE | 0x0020);                        // select I2S source & AM/FM stereo
                iicw4(MSP_CHIP, WRITE_DSP, AM_FM_PRESCALE | (t_presc << 8));        // FM/AM Prescale
    }
    else {
                iicw4(MSP_CHIP, WRITE_DEMOD, MODUS | 0x0060);
                iicw4(MSP_CHIP, WRITE_DSP, I2S_SOURCE_MODE | 0x0220);                        // select SCART source & AM/FM stereo
                iicw4(MSP_CHIP, WRITE_DSP, ACB | SCART_1);                                                // select SCART1 for the audio input
                iicw4(MSP_CHIP, WRITE_DSP, SCART_PRESCALE | (t_presc << 8));        // prescale SCART1
        }

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Yes, it configures the tuner input source differently when it detects your MSP3410D, so will still be expecting a SIF input, hence no sound at the outputs. You will need to modify and recompile Palmod to force it to use the Scart input instead.

Quote:

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Originally Posted by catdog

You will need to modify and recompile Palmod to force it to use the Scart input instead.

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The attached palmod and palmod config can be used to configure this. A new option (s_audio) has been added. If this is set to 1 then SCART1 audio input is forced even if running with a MSP3410D.

It should be noted that this is not the official palmod and is a little different to that which is distributed with the OzTivo image. It should however be pretty compatible with all previous config files.

Updating palmod can stick your machine into a reboot loop if something goes wrong, so I would suggest you do something like that which is outlined here.

The "bin" file just contains the binaries (palmod and palmod_config) whereas the "src" file contains both the binaries and the source code. After making the setting by either using the Audio options menu under palmod_config, or by adding a s_audio=1 to your /etc/palmod.conf file you will need to reload palmod (or reboot).

Thanks Thomson, the new menu is great! I wasn't looking forward to spending ages figuring out how to compile code for the TiVo (and guessing how to best change the code). I was getting twice-daily requests from my wife to get the TiVo going again.

Update: Upon testing the TiVo I found that the only sound I got from live TV was a stuttering sort of noise. Catdog made some further changes to Palmod which gave me silence instead. Upon further investigation I realised that I shouldn't have removed L28 when going from 'MKII stereo mod' to 'MKI stereo mod'. duh.

All working well now!

Hi all,
I would like to get my hands on one of these. How do I go about that. My Tivo already has the Pal tuner mod.

Cheers

I suggest you PM Skolink or catdog.

Peter.

Quote:

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Originally Posted by KEG

Hi all,
I would like to get my hands on one of these. How do I go about that. My Tivo already has the Pal tuner mod.

Cheers

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I'm still part way through designing the PCB for a surface mount version. The one I have is a through-hole prototype built by Catdog. I've been pretty slack and not doen any work on this for ages. I've still got the main decoder chips in the cupboard. I promise I'll get onto it soon...

Well here's where the PCB layout is at.. basically finished.
Any comments welcome, hasn't been sent for fabrication yet so changes can be made.

I finished assembling some of these boards a couple of weeks ago, just waiting on a friend to write some firmware. Will post a photo and start accepting your money soon.
The build cost was $24, plus $2 if you want a HDD style power input socket fitted. Postage $2.50.
They are limited edition 10 units only. 2 already spoken for.

I'd like two, if that's ok, please?

No problem, I'll put them aside. Must chase along that firmware..

2 for me as well.
Thanks

Sweet. My friend (who has a PALmoded TiVo himself) still hasn't written the firmware...might have a go at it myself.

Hows that firmware looking?

I'm a bit unclear if you are offering just the PCB or an assembled board..??

I'd like to put my name down for 2 if they are still available. (and the firmware gets done!)

Umm...no progress on the firmware, sorry. I know it's been weeks.
I'm offering the whole assembled board.