[TriEmbed] CPU

[Scott Hall]

On 07/01/2014 06:59 PM, Antonious Iskander wrote:
> I have a Pentium 4 CPU and I was wondering if I can use it for embedded systems?
>
> Tony

You can, but you are going to have some issues.  That CPU is a general
microprocessor and requires a number of support chips to give you a complete
computer.  The least expensive and most readily available solution is to use a
PC motherboard designed for that processor (it would be difficult to design a 
computer board with all of the right trace lengths, support chips, and debug and
test in short order).  You have many options for I/O and control systems:
multiple-port I/O boards with Linux drivers, using the existing bidirectional
parallel port and serial ports, and of course USB interfaced devices.

Back in the latter 1980's I used some PC clones using the '286 processor running
UNIX and mounted them in manufacturing and laboratory modules - embedding them -
in place of PLC's.  Because the modules were about 30in x 60in, 4 to 6 ft tall
and made of extruded steel and aluminum, it was easy to fit the whole PCs inside
the base area along with all the DIN-rail relays and connectors and such.  I
used Digiboard and clone I/O control boards (8 analog inputs, 32 digital inputs,
16 digital outputs typically) for which there were UNIX device drivers.  Simple
matter to read 16 bytes in (inputs and flags and status), and output 2 bytes for
the I/O.

Because it was a PC, I had full local harddisk storage, plenty of RAM, network
communications, video monitor to display color graphical output, touch-screen
interface, a full OS that ran almost realtime (I didn't demand that much of it)
that allowed me to run COTS applications as well as custom apps, and still
control the robotics in a fully safe and certifiable manner (meaning, it can be
tested by inspectors, follow regulated protocols, and behave the same everytime
no matter the environmental conditions).  I did use industrial grade chassis,
shock mounts, chemical and vibration resistant cases, keyboards and screens, and
made sure all connections and mechanics were to code.  And I built in the
embedded software many fault-tolerant routines and safety features.

Bottom line, to answer your question succinctly, yes you can, but embedding a
whole PC into your project.

-- 
Scott G. Hall
Raleigh, NC, USA
ScottGHall1 at GMail.Com

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