Hi there,

anyone knows more details about the sunplus 8502, a 6502 derivative that is supposedly used in the HP35S calculators?

http://www.eetimes.com/design/embedded/ ... geNumber=1

Thanks
André

Just two key components
On one hand, I was disappointed to see what was actually inside the calculator. That's because it's not a very interesting design. It's just two key components--an 8502 microcontroller and a flash memory chip. Both of those parts are covered by a blob of epoxy, as you can see in Figure 2. The processor is under the bigger blob.
The 8502 is designed by Sunplus Technology, a Taiwanese company. It's based on the 6502, an 8-bit processor that first appeared on the Commodore 64, which was popular around the same time that I purchased my 15c. The flash memory is a generic part, and no specific vendor is used. It's generally based on whatever is available at the right price at the right time.
The 8502 that's used here also contains the system's power management and all the typical chip-set functions. This includes an LCD diver, a keyboard controller, and so on.

In which case its datasheet is here

http://www.datasheetarchive.com/indexer.php?file=DSA00130543.pdf&dir=Datasheet-08&keywords=SPLB31A&database=user-highscore#

SPLB31A
2368 Dots Data Bank
Preliminary
JUL. 24, 2001
Version 0.3