I don't know if it can be useful, at least to me, but it is simply "impressive"!
A simple comparison of the original Lacoste's PIC17C756 to the more modern 9S08AW60 shows a clear advantage of the latter for the hardware power (it has nearly 4 times as much rom and even more ram), a better set of code instructions which will perhaps permit simpler programs but nearly the same speed or only slightly more: infact the mean instruction time lenght of the 9S08 core is nearly 3 clock pulse which compares with slightly more than 1 for the PIC. So 8MHz of the original PIC clock could compare with 20MHz that is the maximum for the AW.
The Author did succeed in achieving a nearly 16kHz sample frequency with 10 banks of processed 256 sample per second: 10 screen/second on a VGA screen with no other chip than the PIC and an LM324. This implies that the maximum frequency which can be processed in base band is nearly 8kHz, from the Nyquist rule. Still no other word than impressive!
This result and perhaps a little better, may be reasonably achieved by the AW60 but, I think, with a considerable effort and some purposely built fixed point math routines. Are you ready to design your own sine and log routines? I am not sure you may easely manage all timely tasks without some jitter, without some buffering. Some external chip could probably help you achieve 3 or 4 times better results, i.e. 2 cpu with separate tasks. I definitely think that nothing smaller than an AW16-60 may reasonably manage a similar task or it's worth it. I think that even the more powerful 'RS08 has not enough resources to do the task at whatsoever frequency and anyway the game isn't worth the candle!
And now an important question.... Did you succeed in retrieving the original code of the Lacoste's article issued in 1998? I did't. It could be very helpful as an example or to try a porting without starting from scratch. If you did, can you write down the link?
Regards,
Encoder