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In article <1365@anasaz.UUCP>, john@anasaz.UUCP (John Moore) writes...
>I am looking for a microcomputer chip with the following characteristics.
>If you know of such a beast, please email.
>  (1) On board EPROM or EEPROM, or built in piggyback socket for same,
>      of at least 4K Bytes - preferrably 8K.
>  (2) On board RAM of at least 256 Bytes.
>  (3) Built in multiply and divide - preferrably 16 bit.
>  (4) 16 bit accumulator and math.
>  (5) On-chip A/D - at least 8 bits, at most 40uSec conversion time,
>      with Sample and Hold. This is optional but desirable.
>  (6) Price less than $30.00 in small quantities
>  (7) On chip interrupting timer - programmable interval.
> 
> 
	What you want exists but I haven't found it for <$30 more
like $75 and up. Hitachi is one source and INTEL is another that have
piggyback versions of their processors. I would suggest however, that 
you use the  Motorola 68HC11A2 available off the shelf
in quantity 1 for $18.00 from Active Electronics. You will need
to add a 74HC573 address latch and an external EPROM. Active has
27C128's for $4.25 quantity one. To do things right you need 1 or 2
inverters. Invert R/W and send it to the output enable on the CHIP,
that is all you have to do. You will get lower power if you also
NAND A15 and E and use that as a chip select.

      I know that is some wiring, but not a lot. The advantages
are you have some one who will sell you just one and low cost, and
its off the shelf. The chip has everything you want.

   256 bytes RAM
   A/D 8 channels multiplexed 16us conversion time built in sampe/hold
     It has a high input impedence you can drive it with 10K ohms
     If you don't multiplex channels (charge sharing occurs then) you
       can use >100k if the signal is not to quickly varying
   Very flexible timer interrupt
	5 timer controlled outputs
        3 time latched inputs
	About a dozen different possible timer interupts

   Built in 8x8 to 16 bit multiply (5 cycles)
   Built in 16/16 to 32 bit divide instruction (41 cycles)

  Built in Serial port, great for talking to your PC...
  512 bytes EEPROM


  The 68HC11E2 has 2kEEprom and can be run as in single chip mode. It
is in your price range if you could squeeze in to that much memory. Bad
news is availabilty is not that good it just took 3months for us to get 3.

  The 68HC11F1 has 1k RAM a non multiplexed bus and internal chip select
logic so you wouldn't need ANY glue. It also accepts a higher clock speed of
4 MHZ. Since the A/D runs off the clock that should give you a 8us conversion
but I haven't checked the specs. I'm sure availabilty on this is not so
good either

  You should expect about 20ma to power everything at 1-2Mhz if you use
a CMOS eprom.


   Active Electronics has Stores in Westborough and Worburn Mass. You
can call information to get their number they will send you a catalogue.
They are one of the very few places willing to deal with the hobbiest.
Standard electronics places have hundred dollar minimums often will
want to do a credit check and generally won't want to deal with you
if you aren't a company or university. Places like Jameco or JDR are 
fine if they stock what you want but their selection is not as good as
Active and they won't order small quantities for you.


				Chuck Parsons
				CHUCK@MITLNS.MIT.EDU
				CHUCK@MITLNS.BITNET