some basic questions about microcontrollers

[Nigel Goodwin]

Quite a few microcontrollers can either optionally run with a "narrower" external data bus, or have different versions with different external data bus widths.

More correctly 'micro-processors', it's pretty rare for a micro-controller to have an external data bus.

As you pointed out, the 68000 was a classic example - as I recall the Sinclair computer (who's name escapes me?) used the 8 bit version, and the Commodore Amiga used the 16 bit version.

 

[rjenkinsgb]

More correctly 'micro-processors',

Very true, it's reflex sprelling from usually discussing PICs etc.

 

[ronsimpson]

The data bus is like a road connecting different parts of an MCU

To add confusion, some computers have both data and instructions on the same bus. Some have data and instructions on separate busses.

I uses the 8085 for a while. To save pins they combined data and address busses. There is a pin that signaled "A" or "D".

 

[Pommie]

as I recall the Sinclair computer (who's name escapes me?)

That would have been the QL (Quantum Leap). Never touched one but remember it.

Mike.

 

[ronsimpson]

the Sinclair computer (who's name escapes me?) used the 8 bit version

Z80 cpu

 

[Pommie]

Ron, that's the ZX81. After that was released the ZX Spectrum also Z80 based and then the QL(Quantum Leap) was released which had a 68000 in it - I think it was actually a 68008. I'm starting to get vague memories of working on a QL!!

Mike.

 

[Nigel Goodwin]

Ron, that's the ZX81. After that was released the ZX Spectrum also Z80 based and then the QL(Quantum Leap) was released which had a 68000 in it - I think it was actually a 68008. I'm starting to get vague memories of working on a QL!!

Yes, the QL was a 68008, with the 8 bit external bus - never seen one though.

 

[Ian Rogers]

That would have been the QL (Quantum Leap). Never touched one but remember it.

Got one of those as well!!! ( a bit turd really )

You HAD to use the micro drives.... worst media ever!!