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Adding PC-Link to MDS-JE640 (like MDS-S50)

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21 minutes ago, NGY said:

(The I2C buffer is really not an issue. I ended up believing that the whole thing can work without it, actually. And do I recall I had found some proof for that, but let me check my notes for it).

It probably would work but not be robust. The uC I2C ports are not designed to drive a cable. Having a read of the datasheet for that I2C buffer gives the background of why that chip is required in such I2C topologies wrt capacitive load and current drive etc. If the USB interface inside the MN10 thing were mounted inside the 640 and wired directly in, I suspect the buffer chip would not be necessary.

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Here is the thing then: the 640 does work now with PC-Link and M-Crew. (See my uncut, lame video at the end - "Welcome to Paradise" :-) .) Yes, it is done, and I feel this is a breakthrough, after a

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8 minutes ago, sfbp said:

this is a Japanese version of the 640 and it says (around) the keyboard port "PC-LINK (keyboard)"

Great find! (Almost jumped on it, but the price ...)

And I am 99.99% sure it uses the same main board pcb as above - see the TOSLINK in/out connectors!

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42 minutes ago, kgallen said:

The uC I2C ports are not designed to drive a cable

No, certainly are not, however, the I2C spec. does allow a certain length of cable, at given cable capacitance and shielding, and at a max. data rate - I am still trying to find the exact quote I noted previously, but until then: "the maximum bus length of an I2C link is about 1 meter at 100 Kbaud, or 10 meters at 10 Kbaud".

So my point is (and I did drop the ball here already), that in order to get this PC-Link thing working on an otherwise not-supported deck does not depend on having this buffer or not (just keep the cable "short", and the PCLK's PS2 cable is indeed very short, I believe Sony's engineers had done their math for a reason.)

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6 minutes ago, NGY said:

however, the I2C spec. does allow a certain length of cable, at given cable capacitance and shielding, and at a max. data rate

Well I guess we could argue details, but I2C is "Inter-IC" so not really designed/intended for off-board driving over a traditional cable - you'd use a spec like RS232 and it's brethren for that.

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Yeah, see my addition above.

So much I hate these messenger/twitter/whatsoever style posting - you cannot really think your words over, or you missed the train ... I go and take a brake break instead ... :-)

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1 minute ago, NGY said:

So much I hate these messenger/twitter/whatsoever style posting - you cannot really think your words over, or you missed the train ... 

Sorry, my bad. Here I go again... :-(

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I2C spec - used to be quite hard to come by, but easily found on't web these days here.

There are three traditional modes, standard-mode @100kbps, fast-mode @400kpbs and Hs-mode @3.4Mbps (not really ever termed baud on I2C).

 

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Sorry for the cut-and-shut picture:

image.png

I wonder if you chaps have a 4-pin or 6-pin connector for CN820 on your 640 main board. Then if R826 and R822 are fitted on your KB board (probably). If so, then I think you could rightly label your KB connector as "Keyboard (PC-Link)" with no changes...

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Well, I absolutely know that my 640 won't work with PCLink. But I will go and look at CN820....

Why does it say "jumper" on each of those two components?

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26 minutes ago, sfbp said:

Why does it say "jumper" on each of those two components?

Zero-ohm link. Commonly used to option in and out circuit elements within a product range. See them all over the place. Could be a wire link but more usually these (and those) days a chip "resistor", 0R.

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13 hours ago, sfbp said:

But I will go and look at CN820....

On the 640 it's next to the rear panel Control-A1(II) connector. This picture is flipped. For you with the lid off, looking from the rear and down it will be to the right just above the rear panel just down from the power supply section (big black capacitors)/just across from the S-shaped heatsink.

image.png

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This is from my last visit to this particular quagmire (I had blocked it out because I got exactly nowhere). I think you will find I've done the obvious connections.

20210407_110207.jpg20210407_110359.jpg

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6 minutes ago, sfbp said:

This is from my last visit to this particular quagmire (I had blocked it out because I got exactly nowhere). I think you will find I've done the obvious connections.

Well there you go, you've been there, done that! No point in me interfering here any more, you've done it!

Hardware is fixed. That's me done. Firmware then. Over to you :-P

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not that i know what you lot are on about,i will just add that the 470 has pc link,dont know about keyboard function though, just my 2p worth to confuse matters even further !

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Going by the specs on MiniDisc.org (I don't have any of these machines), the MDS-JE770 is both PC Link and PS/2 keyboard compatible. The MDS-JE470 has PC Link but no PS/2 keyboard port.

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40 minutes ago, BearBoy said:

Going by the specs on MiniDisc.org (I don't have any of these machines), the MDS-JE770 is both PC Link and PS/2 keyboard compatible. The MDS-JE470 has PC Link but no PS/2 keyboard port.

Good point, actually.

Normally, if both functions are supported on a given (very seldom) model, then those are sharing the same PS2 port. The 470 does have a PS2 port, but on the rear panel (and w/o the keyboard functionality implemented).

DSC00145_470_PS2.jpg.c56cdac83d6db9a81eb535ab39c43aff.jpg

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OK you clever people here is my latest cut-and-shut based on the insight from @M1JWR and @BearBoy

Per @NGY's comments, the PC-Link (raw I2C) is not buffered in the 770 (despite the block diagram suggesting it is, below).

The key here is that if the unit has a keyboard interface, then the I2C (IIC DATA, IIC CLK) also needs to be available raw on the DIN connector. The Keyboard interface has this 5-transistor circuit between the uC and the DIN. Also the PC-Link has these two extra connections IIC BUSY and IIC POWER.

I believe that @sfbp has all these connections in place on his 640, however I need to review the details (but need to pop off for now for a work meeting, so be back later...)

Sorry this is a pdf - exporting as png/jpg/gif didn't have the resolution (however I'll also upload a png just so you can see what's in the pdf, so you don't get too excited...)

Keyboard_PCLink.png

Keyboard_PCLink.pdf

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@NGY, ah, okay. Thanks! I was getting a bit confused because the implementation on the Japanese MDS-JB940 seems to be different, at least it is according to MiniDisc.org

MiniDisc.org says that PC Link on the MDS-JB940 works via the digital optical input (for audio transfer) and can also be controlled from a PC (via Control A1(II) or via the keyboard PS/2 port?)

Unfortunately the English manual I have for the MDS-J940 makes no mention of PC Link as it looks like it was a Japan only function.

Looks like the implementation on the MDS-JE770 was different with everything going through the PS/2 port on the front?

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2 minutes ago, BearBoy said:

MiniDisc.org says that PC Link on the MDS-JB940 works via the digital optical input (for audio transfer) and can also be controlled from a PC (via Control A1(II)?)

I admire the enourmous amount of information on minidisc.org, but learned over the years that I have to take those "facts" with a grain of salt.

The quote above is a bit ambiguous. Using the PC-Link, the audio signal can be transferred either via TOSLINK digital or analogue RCA. Controlling the device from a PC normally happens via the PS2 port (and the PC-Link device), but, the Control A1 has very similar commands/functionalities to that, and - in theory, I have not yet seen this documented - it can be used for the same purpose, as the PC-Link.

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The page for the PC Link kit (PCLK-MN10/MN10A) says:

Quote

Kit includes: Software CD-ROM, USB cable, TOSLink cable, USB to TOSLink/Control-A1 adapter box

But all the photos I can find of the PCLK-MN10 show it having a mini-DIN connector, rather than the 3.5mm jacks used by the Control A1 system.

Probably best we rely on first hand knowledge from people who have used the system rather than what I am scrabbling together from, potentially inaccurate, web sources and my own speculation ;-)

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10 minutes ago, kgallen said:

I believe that @sfbp has all these connections in place on his 640, however I need to review the details

Looks like we are doing a "rat race" here ;-) .

Even I had not posted all my steps and findings here, I feel being somewhat ahead (as been all there already, I even see now where Stephen's solution went wrong), and if you were given me some time to consolidate my knowledge and finally put into practice, we could probably lift all the clouds here at once.

Yes, out of sheer vanity :-) I wanted to come up first with the ultimate solution, in a completed, polished format. But as it is just a pointless luxury that both of us are wasting precious time to discover basically the same thing :-) , maybe better approach is to wait until you also conclude with your findings, then we consolidate the stuff later. I go back to my 640 in the meantime, to do the final step.

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1 hour ago, BearBoy said:

But all the photos I can find of the PCLK-MN10 show it having a mini-DIN connector, rather than the 3.5mm jacks used by the Control A1 system.

I trust you mean by "mini-DIN" the standard PS2 plug, dont' you?

I never saw the PC-Link mentioned as to be used via the Contorl A1 jacks/lines. I think it is possible - to a certian extent, as the command set of the - sort of standardized - Control A1 seems limited compared to the - sort of Sony proprietary - PC-Link bus command set.

 

EDIT:

I wanted to add this note, although it might be obvious: I think the ambiguity around "PC-Link" is coming from the fact, that the deck is connected to the PC-Link device on two lines. One for the (either digital or analogue) audio transfer, and nothing else happens there, but the audio signal flow. The other line is the actual digital control of the deck, that covers controlling the deck operation (record, play, pause, etc.), transferring digital information (track/disc info, etc), as well as some editing functions, etc. The same time, the PC-Link device connects to the PC only on one line, that is the USB. It is possible to transfer audio to a non-PC-Link enabled device via the CAV box, but it lacks the control and info part (ultimately, the communication between the deck and the PC).

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18 minutes ago, NGY said:

Yes, out of sheer vanity :-) I wanted to come up first with the ultimate solution, in a completed, polished format. But as it is just a pointless luxury that both of us are wasting precious time to discover basically the same thing :-) , maybe better approach is to wait until you also conclude with your findings, then we consolidate the stuff later. I go back to my 640 in the meantime, to do the final step.

But on starting this, I did not know you were doing this so embarked on my own investigations per the initial request from @sfbp. I realise you want to present the perfect solution, but even if you share some thoughts then we can collectively learn and collaborate on the way. My reading of your comments was you still had issues to solve. If you want to present the ultimate solution and have all of the answers but are not ready to share, then that "heads up" to us is useful. i.e. I can butt out if this is all old news and there is a known solution yet to be shared.

That said, I don't think I've wasted my own time since I've learned more about an aspect of these machines I hadn't investigated before. However if I'm presenting old news at the frustration of others then I can stop.

Above reads bitter, it is not meant to! Greatest respect to you all here, you are great friends if such can be stated given this is an open forum.

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