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

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

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