SWTPc 6800 vs. Altair 680

joe lang jclang at notms.net
Thu Feb 15 22:29:00 CST 2007

B. Degnan wrote:

> Are the programs from the SWTPc 6800 interchangeable with the Altair 
> 680? Is there a good web reference that compares these two?
there are several differences that affect interchange between
the mits 680 and the swtpc

the acia address is $F000 in  mits
swtpc uses a bit banging PIA at $8004

swtpc uses the mikbug monitor ROM, mits uses a custom
monitor rom that looks a lot like minibug.
(later swtpc systems used SWTBUG and an ACIA)
swtpc has a scratchpad RAM at $A000 mits has all RAM
contigous starting at $0000

swtpc runs at aprox. 900kHZ mits runs at 500KHZ

mits has a configuration register at $F002 swtpc doesn't have one.

both systems use KC standard cassette at 300baud and motorola
S1-S9 records


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