First post, by stamasd
So we know (or at least we think we do) that the SB16 DSPs versions 4.11, 4.12, 4.13 and 4.14 have the hanging note bug, and the 4.05 apparently doesn't. I haven't seen anything anywhere on the web related to what exactly is causing the bug, because there's no information about what's in the DSP.
It is however known that those "DSP" chips are in fact general-purpose 8051 microcontrollers. They have 4kB internal ROM which is custom factory-programmed. MCUs from that generation also have protection mechanisms so that the code can't be directly read externally.
However, there are techniques for reading the code even from protected 8051s.
I think it would be interesting if someone *ahem* could read that code. There are blank versions of the 8051 (8751 actually) that can be programmed with custom code. That may lead to the possibility of replacing DSP chips on the flawed cards with ones that don't have the bug. And since bugged cards are (still) plentiful whereas the non-bugged ones are exceedingly rare (haven't seen one on ebay for months) I thought this may be of interest to this community.
What are your thoughts?
I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O