8051 vs. 68K

[Magnus Danielson]

> Hi all:
> 
> I have been reading this list for a long time although I rarely participate.
> It's good to see an email list where there's so much positive energy!
> 
> Anyway, I've been following the discussion about microcontrollers for patch
> storage and midi stuff and I thought I'd throw in my $.02.
> 
> 8051:	1.  Cheap (<$10 for some of the EPROM parts in volume)
> 	2.  On board UART, parallel I/O, RAM
> 	3.  Stone-age 8-bit instruction set that gets the job done
> 
> 68000:	1.  More expensive
> 	2.  Have to add ROM, RAM, and possibly I/O ports
> 	3.  Reasonably elegant and modern 32-bit instruction set.

So far I agree, but I have seen the 68000 about as dirtcheap as a 8051 so...

> As far as programming goes, the 68K wins hands down.  There is really
> no contest as far as ease of programming in assembly language.  Also, if
> you want to, you can program the 68K in C.  There are a few C compilers
> available for the 8051, but the 8051 architecture isn't really optimized
> for C.  The GNU C compiler, which is free, supports the 68K family well.

It's when you write C code for something like the 8051 you start to understand
that C is nothing but an advanced assembler... but a dran good one...

> You should also consider ease of debugging.  The normal way to debug 8051
> code is with an in-circuit emulator.  With the 68K you can use the GNU
> debugger and do source level debugging over an RS-232 line.
> 
> One drawback I forsee with the 68K in a DIY project is that some of the
> more interesting parts in the 68K family are only available in surface
> mount.  On the other hand, I haven't seen DIP 8051's in a long time either.
> 
> The synth programmer project might be simple enough software-wise that
> you could code it for an 8051 in assembly and debug it by trial-and-error.
> For something more complicated, like a midi-cv converter, I would prefer 
> to use a 68K.

Well, that's why I started to ask if there was some higher goal somewhere...
I agree that the 8051 or anything like it (68HC11 or whatever) will be perfect
for what Juergen originally proposed and asked for. It will even be an overkill
in features and expansion possibilities... but if we would like to create 
something a little more advanced with a few of the ideas I had I think it is
wise to move up the ladder of CPUs and picked the 68k as an rather neat 
example.

In a DIY project I would probably put a debugger/loader in an EPROM and then
have the real firmware in a Flash or EEPROM. This approach migth be very 
usefull
in debugging and software upgrades.

Magnus