CD player chipset programming

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sek

sek

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Joined 2003
#1
Hello there,

I'm planning to modify (read: rebuild 😉) a Technics SL-PG CD player around an old (cheap but good) Philips CD transport. It uses a standard chipset from Panasonic, the MN66271 (a LSI chip for signal processing etc.).

While the manufacturer's datasheet for that IC is easily available, any information about it's microcontroller interface and programming is not. The Technics player 'features' a NEC controller that I can't reuse.

I want to interface the MN66271 to a uC like an AVR. Can someone provide some information on how to interface to and how to program the MN66271?

Thanks,
Sebastian.

PS:
Currently I'm not interrested in a replacement for the MN66271, nor in reclocking or output interface issues, just the interfacing and programming of the LSI.
Reclocked S/P-DIF and AES/EBU output, VFD with convenient buttons and a dedicated quality power supply are planned, though... 😀
 
#2
Okay, after more than 40 views without response I think I make myself a little more clear 😉

The Panasonic MN66271 is an integrated CD player controller chip.
I want to use the good Philips CD transport and it's (not too good) chipset in a DIY way.

What I want to do is: build a good power supply and a digital-out interface for the working transport and chipset. Then put everything into a beautiful enclosure and - almost done.

What this setup is missing would be the user interface, which has to be done with a microcontroller. The player currently features a NEC78042.

While I have no problems to program a microcontroller, I just don't know what commands the MN66271 takes in which format, and how it responds to the controller.

The datasheet (without the software documentation) for the MN66271 can be found here. The IC has a serial interface (3 wire) which could be reverse engineered, but I'm lacking experience and equipment for doing so.

If anyone could provide any kind of information and/or experience on how such LSI CD player chips are interfaced, any help would be very appreciated.

Sebastian.
 
#3
80 views and still no reply... 🙄

Okay, let's get a little broader. Does anyone of you know how to program any such chip using a microcontroller? It's only about the user interface, folks. The controller just has to drive the front panel elements of the CD player. Everything else is fine. 😀
 
#5
From what I can see on the Data sheet, you are on the right pin ,Digital Out is pin 6. Have a look at pin 16 which is a control input pin called DMUTE. I would not be surprised if this is a Digital Out Mute control pin. Data sheet says muted if logic high. Good luck
 

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#7
From what I can see on the schematic these signals AMUTE and DMUTE (analog and digital mute) are coming from pin 32 and pin 33 on IC 501. If you trace the track on the board you should be able to see if pin 32 (output) on IC501 is the only connection. If that is the case you should be able to cut the track and pull the input signal (pin 16)to logic ground . If that does not do the trick, just solder back the connection.
 
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#9
Never mind my earlier posts. On the right side of page 30 in the schematics there are tables telling us the logic status on the pins when power is on. It says 0 volt on pin 16. That means not muted. So the problem has to be elsewhere. By the way, with what kind of instrument are you doing the measurements ?
 
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#10
Thanks for looking, its fun to find out..🙂

Pin6 the multimeter voltmeter is saying 0,08 volt, and my very old scope is telling the same I think, but its kind of blurry to tell exactly.

Allready made a connection on pin 6, with a toslink (http://www.farnell.com/cad/1708371.pdf), so ready to play. Only needs to be activated I guess.

I have been looking into a another service manual of an other type cd changer, here they use nearly the same ic101 for the same purpose, but this one does have toslink out and also using pin 6. So maybe this manual is nice to do crosscheck, maybe you see here the answer? please see page 22 ic101 https://www.scribd.com/doc/251045332/alpine-cha-s624-service-manual

I hope you see the answer?
 
#12
I was just bussy with that, so here the results.

multimeter is saying 8,1 mv on pin 6

The scope is saying 15 mV when on pauze, and 20mV when playing

Because I saw in the other service manual a resistor between pin 6 and the toslink, I did that over here too, with a 470ohm in serie. Also did a 100pf over vcc and gnd as protection.

I do not see the toslink light up, how do I check if the toslink is not broken? accidently put 7 volts on it instead of 5 volts.
 
#13
The crossreference cd player chas 624 with optical out, I also own, so I have measured on the toslink, and here they multimeter is saying 17 mV. page 23, pin 4, on the toslink ic940. So pin 6 is connected to a 470ohm resistor, and then I measured 17 mv. THis means I;m not sure if the table is correct wich was saying 0,04 volt.

So I would expect the same of the chas 1214 after pin 6.....

Something is taking care of the difference.
 
#14
There is a chance that the output is blown. Could you by any chance have accidentally connected the output to pin 1 (GND) instead of pin 3 (INPUT) on the Toslink before you connected the 470 ohm series resistor? Take a look at the numbering here and watch out for Top view and Bottom view.
 

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#15
Thanks Dacen,

I'm using this one: http://www.farnell.com/cad/1708371.pdf?CMP=AFC-AN-NL-ALL-570234

I think I did the numbering correct, but I have exceeded the voltage, maybe with 7,8 volts. And 7 volts is the ultimatium limit, I saw that 5 volts was better, so now I have 5 volts.

I just ordered a new one, hopefully I have it tommorow and otherwise the day after. Perhaps its broken but not sure.

But what do you think of my last post?
That I measure the chas624 and its 17 mV with resistor 470ohm on pin6, and in the table they talk about 4 mV.

The Chas 1214 is the one that I would like to make an toslink connector out, but here I measure 8 mV on pin 6
 
#16
You should see a clear puls train at TTL level 0 - 5volt on the output pin 6. Even when not playing the puls train is there to keep the SPDIF receiver in the other end in lock. To me it seems that the output on pin 6 is blown.
 
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