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

Started by Andreas December 6, 2004
Hi!
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,
Andreas
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
instructions.
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
intensive.

Deepa
--
http://www.EventHelix.com/EventStudio
EventStudio 2.5 - Embedded System with Sequence Diagrams

Andreas wrote:
> Hi! > 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, > Andreas
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