[sdiy] Siel/suzuki Keyman...what are these chips?? IMP 8543 and Motorola SC93355P?

[Bob Weigel]

They both have Siel and what appear to be perhaps version codes in the 
original die so these were probably oem parts.  I'm curius because some 
of the sounds on these are fairly decent analog sounding though of 
course you can't really change any parameters... I wonder if these just 
*might* be a circuit bender's delight though...  Anybody seen data 
sheets on them?  I wound up with both the Keyman PK-49 and 61 from the 
bunch of stuff we got from Tucson. -Bob