dlarson@blake.acs.washington.edu (Dale Larson) (03/20/90)
A friend would like to increase the performance of his A2620. He plans
to upgrade the 881 to a faster 882. He also would like to increase the
speed of the 020 and of the memory. He has ordered a 33mhz 020 and will
be getting a 4*7.whatver mhz clock. What, if anything, needs to be done
to make this work? What performance increase should be expected from just
a faster 020 (or a faster 020 and faster memory, if necessary (i.e. the
2620 can't provide enough wait states for 100ns parts))?
Thank you for your email responses which I will forward to my friend and
summarize for posting here.
--
There are two ways to improve on human factors in computing:
Make the programmers less stupid and/or make the users less stupid.
Both are necessary, neither are likely.
-Digital Teddy Bear (dlarson@blake.acs.washington.edu)daveh@cbmvax.commodore.com (Dave Haynie) (03/20/90)
In article <6299@blake.acs.washington.edu> dlarson@blake.acs.washington.edu (Dale Larson) writes: >A friend would like to increase the performance of his A2620. He plans >to upgrade the 881 to a faster 882. That works just fine. The manual explains the details, but basically, you yank out the '881, solder in a faster crystal as desired, and change a jumper. >He also would like to increase the speed of the 020 and of the memory. He has >ordered a 33mhz 020 and will be getting a 4*7.whatver mhz clock. What, if anything, >needs to be done to make this work? Would you settle for a minor miracle? Basically, there is no way to make the '020 clock any faster on the A2620 without major surgery. The 68020, 68851, and clocked PALs all get their clocking from a 14.3MHz clock generated with an XNOR of the 7MHz and CDAC system clocks. The A2620 design is what we in the Amiga Coprocessor Card business call a _synchronous_ design. That means that the clock of the CPU, 68000 interface logic, etc. has a specific relationship to the Amiga system clocks which never changes. The logic depends on being locked to the Amiga clocks, and won't work at any other speed. >What performance increase should be expected from just a faster 020 (or a faster >020 and faster memory, if necessary (i.e. the 2620 can't provide enough wait states >for 100ns parts))? The A2620 does have provision for faster memory, though it all has to be of the faster variety to work. All 80ns memories and most 90ns (kind of a weird part) memories are OK. To enable the faster memory cycle, change J500. -- Dave Haynie Commodore-Amiga (Systems Engineering) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy Too much of everything is just enough