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#112219 - 01/18/18 02:21 PM Re: Epoch Cassette Vision and uPD77X chips [Re: seanriddle]  
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plgDavid Offline
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Awesome update, thanks. When you mean matching Kevtris's ROM dumps, that was for which type of chips? if its upD77X, given the procedure I could dump the rest of my cartridges.
Cheers

#112224 - 01/18/18 07:02 PM Re: Epoch Cassette Vision and uPD77X chips [Re: plgDavid]  
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ssj Online content
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Sean, did you ever check with Kevin if he is able to dump these electronically? I recall checking with him a few years back and iirc he hadn't tried it by then.

I recently sent a Hanimex HMG7900 machine and some games to PeT so he could have a look at it and the machine chip is from the same family (upD779C).

ECV games aren't particularly expensive so even if the dumping process ends up being destructive wouldn't be a big deal I think, I'd love to see this one emulated that's for sure. ECV, HMG-7900 and Gakken TV Boy are some tough nuts to crack.

#112225 - 01/18/18 10:55 PM Re: Epoch Cassette Vision and uPD77X chips [Re: plgDavid]  
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seanriddle Offline
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Turns out I had already Whinked the chip, so I took pics with the top metal removed. I also re-composited the top metal pics and created a larger die shot: https://seanriddledecap.blogspot.com/2018/01/blog-post.html

plgDavid- I decapped chips from some games that Kevtris had already electronically dumped so that I could figure out the physical location of the ROM bits. I used that information to visually dump Fabulous Fred's D557 and Computer Gin's D650. So I was hopeful that the ROM layout was the same in the D77x.

ssj- Not recently. A couple of years ago I sent him a Cassette Vision D777 that incog had sent to me.

#112245 - 01/20/18 09:16 AM Re: Epoch Cassette Vision and uPD77X chips [Re: plgDavid]  
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seanriddle Offline
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Unfortunately the D777 ROM is unlike any of the other NEC chips I've decapped. There are actually 2 ROM areas: a smaller one at top center with 50 rows of 114 bits, and a larger one across the bottom of the die with 64 rows of 360 bits. The smaller one has 7 columns of 16 bits and one column of 2 bits. The larger one has 24 columns alternating between 14 and 16 bits.

I transcribed both of them visually:
www.seanriddle.com/d777_1_raw.bin for the smaller one and

www.seanriddle.com/d777_2_raw.bin for the larger one.

Since 114 isn't divisible by 8, the first file has 50x15 bytes; each row has 6 bits of padding added to the end. I also rotated the 1st ROM array 180 degrees before transcribing so that the address decoding for the 2 ROM areas had the same orientation.

Because I dumped these visually, there are likely a few errors, so please double-check them

#112601 - 02/13/18 09:13 AM Re: Epoch Cassette Vision and uPD77X chips [Re: plgDavid]  
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ssj Online content
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Anyone managed to figure something out of the dumps?
The D777 is an all-in-one micro iirc as the console board doesn't have any video or audio hardware so maybe that would explain the 2 ROM areas.

#112604 - 02/13/18 02:29 PM Re: Epoch Cassette Vision and uPD77X chips [Re: plgDavid]  
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plgDavid Offline
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Hey Thanks Sean!
I just noticed this topic was updated.
Wow, that is some serious puzzle.

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