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  1. #1
    Join Date
    Dec 2005
    Location
    Christchurch, New Zealand
    Posts
    463

    Question NICAM decoder with Micronas MSP3430D (MKII stero mod)

    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).

  2. #2
    Join Date
    Mar 2005
    Location
    Hamilton, NZ
    Posts
    196
    Quote Originally Posted by Skolink View Post
    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).
    Briefly looking at the Palmod source code:
    Code:
    	// 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
    	}
    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.

  3. #3
    Join Date
    May 2004
    Location
    Wellington, NZ
    Posts
    477
    Quote Originally Posted by catdog View Post
    You will need to modify and recompile Palmod to force it to use the Scart input instead.
    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).
    Attached Files Attached Files

  4. #4
    Join Date
    Dec 2005
    Location
    Christchurch, New Zealand
    Posts
    463

    New Palmod

    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!
    Last edited by Skolink; 21-07-2007 at 01:13 PM. Reason: new pamod, keep L28

  5. #5
    Join Date
    Dec 2005
    Location
    Christchurch, New Zealand
    Posts
    463
    Sweet. My friend (who has a PALmoded TiVo himself) still hasn't written the firmware...might have a go at it myself.

  6. #6
    Join Date
    Mar 2007
    Location
    Auckland, New Zealand
    Posts
    5
    2 for me as well.
    Thanks

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