nesdev.org

Let me introduce to you: YM2612

And it's clone: TA-07

These chips have different technology, but it still shows that the clone is made almost by copy-paste technique. For example, you may look at it here. So, very soon we can know almost all about YM2612 and it's clones. Feel free to use it as you wish. You can start to search peoples, which can read these photos, or learn it yourself.

Check this out!


So, this picture 24516x21770 pixels and 116MBytes. It's too big for FileDen, and all pichostings, so I placed it on filesharing service. Someone of you can rehost it to better place.

1. DAC is 8bit, not 9bit.
2. DAC seems to be one not only for 6 channels, but for left/right output too. But I don't get it: oscilloscope shows channel synchronization:

Perhaps they used the capacitance to store the current signal level. DAC place at upper right corner on picture. All analog pins can easily be traced to him.

The first step is to identify all the blocks in the picture. Interestingly, below the center at right side there are some matrixes, perhaps this is the operator unit and the calculation tables for the level of the envelope and sine. And they're seems 14-bit. On the left side above the middle is likely array of registers.

Learning, thinking and posting here.

PS Any part of picture can be recaptured with better quality. Source PSD file was 1,5GB. :3

Nice!

Definitely interested to learn what secrets this chip has been hiding...

1988 ⓂYAMAHA

The copyright-like exclusive rights in an integrated circuit symbolized by Ⓜ expire after ten years. After that point, copy and paste becomes legal, assuming that there are no patents in the way. (Patents expire twenty years after the original filing date, subject to extensions for undue delay at the patent office or undue delay in getting regulatory approval for marketing. The FM synthesis patent expired in 1995.) When was the TA-07 first seen?

tepples wrote:When was the TA-07 first seen?

About 1994 year.

I came as rainbow

Nemesis wrote:I should add, I'm not really sure from looking at the circuit if the DAC really is 9-bit or 8-bit. It looks like 9 data lines come up to the DAC, but one of them gets whisked away and I can't quite figure out what happens to it. At a guess, I'd say it's really a 9-bit DAC, but one of those is the sign bit, so it gets applied later on, after the remaining 8 bits have been run through the ADC conversion table.

You totally right! Analog value matrix is 8x32 (256 levels). 9th bit is a sign.

Sign bit conect DAC matrix to AVCC or AGND via Source/Sink power switches. That is why between two samples on MOL/MOR are 1/2 of AVCC. Thus, 8bit DAC pulls up to the AVCC or pulls down to the AGND which depends on 9th sign bit. Whoah.

OK. Look here:

Very interesting: all 9 bits routed to control unit. Upper 8 are goes from 8-bit register 9above control block) and rest one bit goes (by another route) somewhere inside control block. So, are we able to whole 9 bit DAC programming?

Sorry for revive this, but I'm VERY VERY interested in the FULL SIZE image of 116mb and it was deleted from depositfiles. Someone saved it in a HDD before the removal?

Thanks