Help Wanted - "Sid Vicious" - developing Pic Vic s

[Diddl]

SIDAvr interfaces a SID to an AVR and provides MIDI. It does not emulate a SID. SwinSID (http://www.swinkels.tvtom.pl/swinsid/) is the emulation.

Yes you are right. But this SwinSID seems to be a good replacement for a SID. So it would be a good choice for the VIC-20 sound project of Ian

[Vic20-Ian]

...it somehow seems wrong to rob a perfectly good C64 of it's voice just so that a VIC-20 can have a better one.

Heh, several of the collected C64s here are not perfectly good.

Like the one I used to repair another
for an elderly lady last Saturday,

I think most would agree that organ donation is better than cannibalism

Googling SwinSID now.

@ Diddl - why is the soundgin not a good idea? Interfacing?

Re comments on baud rate, do the filter settings need to be changed more than 400 times per second to play music on SID? (estimated from 3 filters, 2 codes per filter change command * 400 / sec = 2400 baud or am I out by a factor of 8 there for bps? which would be about 50 filter changes per second)

[Vic20-Ian]

My first steps are to get the RS232 board and try out with PC then find a way to develop an interface for a Vic cart.

RS-232? It is too slow for sound, VIC only supports 300Bd (max. 1200, doesn#t work really).


It would be better to integrate the sound chip on the expansion port.

I would take an 8 bit baby and wire it for a prototype. i made this so while developing Fe3.

link to 8 bit baby

The Votrax talks to the Vic at 2400 Baud doesn't it?


http://sleepingelephant.com/ipw-web/bul ... ght=votrax

http://sleepingelephant.com/ipw-web/bul ... otrax+2400

[Mike]

Ian, the Votrax can work with a serial connection, because it is smart enough to synthesize the speech from only a few data bytes. Think of it of as a small computer for itself, with only a connection to the VIC, a little bit RAM, a ROM table with phoneme waveforms, and simple digital to analog converter for sound output.

Sound chips like the SID are "dumb" compared to this, still there are oscillators, hull curve generators, digital to analog convertors, mixers, and filters built-in which can achieve the same effect as a dedicated voice synthesizing chip. But for this, a CPU does direct access to the chip registers, and changes the internal parameters quite more often than would be possible over a serial connection.

[Vic20-Ian]

Mike,

how do the Soundgin and speakjet work to produce sound from 5 or 6 oscillators then?

Speech is from an allophone table to oscillator setting conversion as I understand it so similar to the sp0256 / votrax allophone chip type setup - controlled serially.

Surely 2400 baud = 300 bytes per second = 150 commands per second and assuming 2 bytes per register change = 50 register changes per second for 3 oscillators.

Q for some sid musicians out there - How many register changes are needed on the 3 oscillators on a real SID per second?