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Address Sniffing an EPROM

May 21, 2012

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The one page BASIC SID Benchmark.

How do you make sure the SIDs you bought from Ebay are fully working before giving feedback? Or, you are the seller and you want to claim "100% fully working SID all voices. All Filters guaranteed!" and double check your stuff before you send the chips? How do you make sure the SIDs that are in the old C64 in your dad's basement works before attempting a MIDIBox SID , sammichSID or other similar project? (Or midway through the project your dodgy soldering skills makes you wonder if you just blew out your 50$ SID?) You find certain .sid files sound ODD on your setup and you want to be sure all waveforms of all channels sound good across the entire frequency range? You want to make sure the filters are behaving within tolerance, or you want to quickly compare its frequency response with a third party? or... You are a nerd that does SID research, collect SIDs like Pokemons and compare each of them with scopes and frequency analyzers? A: Sure I'm interest...

chipspeech Diary, Part 2

Last summer I spent a good part of my late night research time on Texas Instrument Voice Synthesis Processor (VSP) LPC10 decoding chips. TI made LOTS of these from the late 70s to the late 80s, both for the OEM market and for its own use, under different names. They usually prefixed them TMC or CD for internal use, and TMS for OEM use, but their naming was not always consistent, which leads to lots of confusion. The goal for chipspeech is to playback LPC10 streams coming from any Texas Instrument device/software and to do so in a sample accurate manner. We are very close to that goal, but since I found no less than 8 variants of VSPs - all of which had to be accounted for in my emulation core - I'm convinced in fact, that there may be more. A variant is a unique combination of the following features: Pitch encoding format (5 or 6 bit indexes) Energy ROM look-up table Pitch ROM look-up table K (lattice filter) ROM look-up table Voiced c...

Last minute addition: Odyssey 2 (P824x) VDC chip!

Building a software product and analyzing hardware are two very important facets of a product like chipsounds. Do mostly the analysis and you have a very techy app that no one understands, do only the former and you miss that that hands on feeling and the smell of printed circuit boards. So this weekend I took a little break from coding (which is very close to done anyway) And looked at the few consoles in my lot that are not fully analyzed yet (I will add more chips in updates). And decided that chipsounds 1.0 required the Odyssey2. The interesting thing is that there is no sound-coder-friendly documentation on the P8244/P8245 online yet, so I figured might as well publish everything I've learned so far. My research consisted in confirming Sören Gust's info from g7kbios.pdf and to go further in trying various combination of tones and timbres that would be possible on the console itself without using IRQ based resynchs and also to check on MESS's source code theory of the...

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Address Sniffing an EPROM

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