How to estimate I/O and calculation power of a micro?

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I try to choose a micro fitting for my application.
I'm not sure how to estimate the power rating of the micro.
Basicly, I must handle 1 parallel printerport (with connected printer),
1 chipcard drive, 1 serial link to a GSM modem, a 4x4 keyboard matrix,
4x20 alphanumeric display (with its own display driving controller) and
4 serial 38,4 kBit/s links.
In a worst case all actions (keyboard hit, entering chipcard, display
output, I/O...) can take place at a time. Further, there is the
processing of the I/O data. Let's assume the task times are known.
Now, how much MIPS do I actually need? Is there a kind of approximation
formula or something?
Thanks in advance!

Best regards,

Re: How to estimate I/O and calculation power of a micro?
1. Estimate the approximate number of C code lines that will execute to
performing a transfer on the serial link.
2. Multiply this number by 4 to obtain the approximate number of
3. Use the rate of the link to estimate the total instructions that
need to be executed per second. This
should give you a reasonable estimate.

Other operations on your processor do not seem to be computationaly

EventStudio 2.5 - Embedded System with Sequence Diagrams

Re: How to estimate I/O and calculation power of a micro?
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IMHO, most of your processing load comes from the serial lines:
the 5 lines will generate up to 20000 interrupts / second
unidirectional and double that bidirectional. You have only
25 us per character including all overhead, if all the serial
connections are full duplex active together.


Tauno Voipio
tauno voipio (at) iki fi

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