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From: whit@milton.u.washington.edu (John Whitmore)
Newsgroups: sci.electronics
Subject: Re: microprocessor wanted
Summary: The specified device will be called a DSP, not a microprocessor.
Message-ID: <1991Apr24.232426.24458@milton.u.washington.edu>
Date: 24 Apr 91 23:24:26 GMT
References: <119279@unix.cis.pitt.edu>
Organization: University of Washington, Seattle
Lines: 30

In article <119279@unix.cis.pitt.edu> fmgst@unix.cis.pitt.edu (Filip Gieszczykiewicz) writes:
>	I need a microprocessor with the following specifications:

>	o	8-bit (16-bit would be nice)
>	o	~10MHz clock
	Um... is this a maximum, because of memory speed or battery
power requirements, or a minimum?  Or do you care more about MIPS than
clock speed?
>	o	ability to address 64K of RAM (more would be nice)
>	o	BUILT-IN floating processor (that's the problem)
>	o	CHEAP (under $40)

>	I realize that the 80486 fits the above specs
	as does the 68040

	Almost any inexpensive CPU with floating point and relatively
high throughput will be a DSP; the so-called 'microprocessors' are 
usually more logic controllers than floating point engines.  Prices
on DSPs vary, as do the particular floating point capabilities (the
least expensive units actually are FIXED POINT, which is ever so
slightly different from floating point).
	The TMS320C25, with 64k data +64k program memory space,
runs at 25 MHz and costs circa $90.  Motorola's 5600x and 96xxx
offerings, Analog Devices, and even AT&T, will undoubtedly be
able to fill your needs (all except maybe price...).
	The multiply/accumulate time on the TMS320C25 is 100 ns;
could you perhaps use half as many processors, if each is twice
the speed you were aiming for?

	John Whitmore