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Topic: Floating Point Co-Processor (Read 4380 times) previous topic - next topic

vogel1230

I ran across this device that provides a 64 /32 bit floating point co-processor for arduino. No sure if this is needed, but I thought the scientific measurement forum might be the place to post the links.

product page:
http://micromegacorp.com/products.html

datasheet and other info arduino related info attached

robtillaart

Thanks!
Is a known device, Nick Gammon did some testing with the 32 bit nephew of this FPU.
See - http://arduino.cc/forum/index.php/topic,101298 -
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

el_supremo

#2
Jan 16, 2013, 12:12 am Last Edit: Jan 16, 2013, 12:25 am by el_supremo Reason: 1
I have the 32-bit one. IMHO it isn't really useful for a 16MHz Arduino. IIRC the FPU is based on a processor whose clock is only twice as fast as the Arduino and it doesn't have floating point hardware. The thing that kills it is the amount of time required to send your data to the FPU and then get the results back. If you want to offload some computations while the Arduino does something else it might be useful.
Before you buy one read the instruction timings in the data sheet, figure out how much data you have to shovel in and out and decided whether it will save you any time.
[addendum]
I should mention that it has several features that I haven't used. For example the NMEA sentence parser and 2 12-bit A/D converters
Pete

michinyon

I came to the same conclusion,  and figured out it was better to get a faster computer with floating point in it.

el_supremo

Yep, or even just a faster computer without floating point hardware. The fpu emulation might be fast enough that some apps will work without fpu hardware.

Pete

robtillaart

Quote
For example the NMEA sentence parser and 2 12-bit A/D converters


So that would make it useful when doing some geo-math on coordinates (e.g. distance to some point calculation involves gonio)
or for analog sensors that need some math formula applied e.g. thermistors that need some 3rd degree non linear formula.
or an FFT on 2 audio channels or ...

IN short as a preprocessor before sending the data to a duino.
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

michinyon

Yes,  but I don't think it is very easy to organise it as a preprocessor between some device
and the arduino.   Unless you had two arduinos,   and one of them was there just
to manage the input and output of this device.

pYro_65

If it can do large FFT's the time saved may justify the communication overhead. If it can be programmed with user code, then it could be left alone for a while doing an expensive task of any kind.

robtillaart

Quote
Yes,  but I don't think it is very easy to organise it as a preprocessor between some device and the arduino.

Why not? OK maybe for some,  but the FPU has autonomous inputs serial?
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

michinyon

Well I read the instructions several times and it didn't seem very clear to me.  Perhaps I should
actually obtain one and get it to work.

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