From: cs000rdw@selway.umt.edu (Richard D Warner)
Subject: UART-CPU-ROM-RAM subsystem
Keywords: cheap, low-cost, small $$$
Organization: University of Montana
Lines: 21

	This is a followup post to something I've written previously.  Several
people responded with good information, but I don't think I communicated 
exactly what I am looking for.
	I'm working on a custom I/O device that will communicate with a host
via RS-232.  My custom circuitry will use an 80C186EB or EC CPU and require
about 64K of RAM (preferably FLASH RAM).  In looking around, I see that lots
of people have engineered UART-CPU-ROM-RAM subsystems that are ready to be
interfaced to your custom I/O devices.  It's been done so much, that it 
would be best if I can avoid reinventing a system.  It just needs to use
an 80C186 (or 188) CPU, and be able to load a program from the host then 
transfer control to that program.  Well, there's one other thing the ROM
needs to know how to do.  It should have routines to send and receive bytes
to/from the host, that utilize the hardware control lines (DTR,RTS,DTS,CTS).
Everything I've seen is in the $200.00 and up range.  That's too much for
this application.  I need something around $100.00.  The CPU has the UART
built-in, so you're only looking at a few chips.  Does anyone know a 
company that markets a good board in this range, or some public domain 
circuitry I can use?  Thanks in advance for the info.

Rich

