Russ, check out the Cypress PSoC. I swore i'd never touch another M8 MCU
but this chip is lookin mighty tempting. 8 digital configurable blocks, 12
analog blocks, 1 MAC etc... All under US$3 (10K) for the 20 and 28 pin
versions.

Cheers
Terry

At 12:49 AM 7/11/01 +1200, you wrote:
>Well, sort of
>More a "which way should I jump" challenge.
>Smallish run commercial project - say 100 to 200 units.
>Cheaper would be nicer but labour costs will predominate.
>Lower than higher current nice.
>
>Processor sends serial to a printer, serial from a GPS, serial from a card
>reader, reads/writes a 32K IIC eerom, talks to a central processor.
>All inter peripheral links are N81 ASCII at true RS232 levels. All data
>links are at 4800 baud.
>
>Want to get this going with minimal effort and cost. At present Scenx with
>virtual peripherals seems the probable easiest.
>
>3 x 4800 UART receives
>2 x UART TXs
>1 x EEROM read/write
>GPS data filtering
>Data request/write control
>Data direction to/from peripherals.
>
>Send data to central processor via 4800 baud link.
>Abort GPS read if card reader starts.
>Can handle card reader and eerom write if both overlap.
>Maybe queue card reader if occurs during eerom read but maybe abort block
>read and repeat thereafter.
>eerom read / write is always either 2 bytes or 64 bytes.
>
>GPS should have output filtered to normally only forward RMC string (coz at
>4800 baud this takes about 15% of channel bandwidth with 1 second update
>whereas all standard messages take about 85%).
>
>With virtual UARTS with say 4 samples per bit at 4800 baud that's 50 uS
>polling cycle.
>Scenix handles with ease.
>20M PIC also really.
>Just maybe a 4 M PIC (maybe).
>
>Anything out there with 3 hardware UARTS and costs about nothing ?(I'm being
>lazy)
>
>Could just about do this with 8 i/o lines (2 x TX, 3 x RX, 2 x IIC = 7)
>Something else will crop up needing at least one more.
>
>Modest EEROM on chip would be nice but not essential.
>
>Scenix is not cheap and is power thirsty but the virtual peripherals do look
>attractive.
>
>Any thoughts???
>
>
>      Russell McMahon
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