they know everyone is using cortex so the have to com up with some sort of argument as to why they should all get learn a new architecture, they can only get in one place, and get new tools
-Lasse
Where you looking for cpu's with dual-precision FP? Did you find any smallish ones? I'm looking for such a processor myself and it seems only the bigger CPU's have DP FP. Seems to start with Cortex A5 and this e300. Processors like M4 and SHARC only have single precision FPU's.
-- Stef (remove caps, dashes and .invalid from e-mail address to reply by mail) To get something clean, one has to get something dirty. To get something dirty, one does not have to get anything clean.
MIPS/ImgTec only announced their first microcontroller core with FP support a few months ago (and I'd really rather not Microchip tried to roll their own. If they did the errata sheet would probably mention something about badgers mauling your face.)
-a
FP aside, i am more interested in the 12 bits A2D and 512K sram. Hopefully, they won't mess up these too badly. At least they have 64 pins package. Most M4 start with 100 pins.
The MPC5200 seems to be the most embeddable one that I've found.
DP floating point hardware is just big; that probably drives the "only big processors have DP floating point" issue.
What are you doing? You may be able to solve your problem with fixed- point arithmetic and cleverness -- in my recent search, had I not talked my way into a spot on a big processor I would have seriously considered
64-bit fixed point, and there's a huge class of control system problems that just can't be done with 32-bit floating point that work great with 32-bit fixed point.-- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Some people like to dig into the guts of things and compare on features they can't measure. I don't care a rat's rear how big the FPU is, I care about the measurable features, price, cost, power, package size. The die size may impact these, but so do many, many other parameters. So I worry about the results I can see, not the ones I can't.
-- Rick
So take a look at this:
Olaf
Buy Renesas, they can do 100Mhz with 0Wait and if it is not fast enought, use a SH7264 with 1MByte internal Ram. Ups...there is now a new SH7268 with 2624KByte internal Ram!
The SH2A had 16 Register bank to switch very fast for every IRQ. :-p
Oh..and 64kByte Dualport Ram is cute, too....
Olaf
I dont know how you come to that conclusion
200 / (1+2) = 66 MHz.And as someone else pointed out, the Renesas parts can run the flash at
100 MHz.BR Ulf
Good catch on my bad math. Should have said 60 to 70 MHz.
Or you can run it on sram at 200MHz+.
On a 80MHz MX, i have done OC 120MHz.
On a 200MHz MZ, perhaps we can try 300MHz.
Be sure to be able to stop SRAM OC with boot option. Otherwise, you might not be able to reprogram the chip.
So far I have similar findings, thanks for the confirmation.
This is a measurement that requires (amongst other things) a non-linear fitting procedure with the Levenberg?Marquardt algorithm on a few thousand samples. We already found that disabling denormals does not significantly affect the results (but it is noticeable) and gives a huge speed increase.
Going back to 32-bit floating point or 64/32-bit fixed point will require testing on a lot of data and of course modifying the code (there are also some math lib functions involved in the calculation). This is not off the option list, but needs to be compared with 'safe' solutions (sticking with double precision floating point).
-- Stef (remove caps, dashes and .invalid from e-mail address to reply by mail) He: Let's end it all, bequeathin' our brains to science. She: What?!? Science got enough trouble with their OWN brains. -- Walt Kelly
Just had a better look at the Cortex-Rx, I somehow skipped over this one earlier. The R4 always has a double precision FPU, the R5 and R7 have an option for double precision or optimized single precision.
TI has for instance the Hercules safety controllers with R4 core, starting at LQFP-144 packages. Interesting, not sure it can handle the memory requirements for our application (which are still under investigation btw).
The safety aspect of these controlers may be a plus for the intended application.
-- Stef (remove caps, dashes and .invalid from e-mail address to reply by mail) There comes a time in the affairs of a man when he has to take the bull by the tail and face the situation. -- W.C. Fields
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