Dale Mentzer wrote:
>
> I have been thinking about this a little, and the idea of using the
> CPU reduce hardware costs is not new at all. Those on the list who
> have or had a Commodore 64 may remember that there was not a UART
> chip to handle communications with a modem connected on the User
> Port. This chore was handled by the CPU via the OS. The native code
> of the Commodore OS was even limited to 1200 baud and it was only by
> rewriting this code withing a comm program that C= users were able to
> advance to 2400 baud communications. I just goes to show that no bad
> idea every dies. :)
Hi Dale;
It really isn't that bad an idea if the processor has nothing much else to do.
I recently finished a little controller containing a real-time clock in code
wherein the time gets set via a com port on a PC.
The serial loop runs at 19.2kbaud and is implemented in code to keep the cost
down. Since, in this case the micro has nothing else to do except keep time,
and in the case of the Commodore it has nothing else to do except keep up with
your typing, these are not, IMHO, bad uses of processor power.
Of course, these usages were written in assembly language. To drain away 80%
of the power of a 75Mhz pentium to simulate a modem with software written in
"C" while trying to run Windows and a webbrowser, also likely written in "C"
IS a bad idea. (IMHO)
- Clarence Verge
--
- Help stamp out FATWARE. As a start visit: http://home.arachne.cz/
--
