[sdiy] MIDI too fast?

[Ullrich Peter]

Hi!

>Wonder if the cpu's on these old synths could be replaced with  
>something faster that has the same instruction set or over clock the  
>cpu, without screwing up the functionality... I would imagine it would  
>depend on how the coding was done, if the programmers used the CPU  
>speed to calculate timing that would probably mean you are stuck with  
>that CPU...

Some of the older synth used the 8051 series microncontrollers.
Especially these microcontrollers that are still alive have been 
Upgraded with faster cores and some of them should perform like the 
original part but faster execution times. So the peripheral parts have to 
react the same (timers, uarts) but the execution can be optimized.
With these new parts a software upgrade that adds some functionality 
Or improves the standard functionality or timing (f.e. midi latency) would 
be possible.

Some of the newer parts have different chip housings, so maybe adapter 
PCBs are necessary.

Some of the improved 8051 series are/were from:
Dallas(Maxim), Silicon Labs, Intel (80c251)

But there were also some manufacturers that took the standard core and 
only made it faster. Years ago I got a sample of a 40MHz 8031 CPU (normally 12MHz).
The problem that time was to find an eprom that could deliver the code in the short time...

Nowadays the fast 8051 CPU that go even beyond 100MHz work with integrated 
flash memory that has been optimized for the speed. So if you want to use such a chip
you have the remove or disable the eprom in the synth.

Ciao
Peter


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