-have your cake and eat it too! "rasberry pi"

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16 Aug 2011 01:36 - 16 Aug 2011 02:13 #12513 by M4MazakUser
anyone rekon one of these would run emc2?

www.raspberrypi.org/

they do have some digital outputs etc on board as standard,


@...............$25................WOW!

Roughly 16 lines of GPIO, plus I2C and SPI, all at 3.3V
Last edit: 16 Aug 2011 02:13 by M4MazakUser. Reason: i/o details

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16 Aug 2011 02:08 #12514 by jmelson
M4MazakUser wrote:

anyone rekon one of these would run emc2?

www.raspberrypi.org/

they do have some digital outputs etc on board as standard,


@...............$25................WOW!

A year ago I sent a $149 BeagleBoard to the ARM maintainer of the RTAI project, hoping
he could develop an RTAI port in a reasonable time for the TI OMAP chip on it.

Well, a year later, he has gotten a partial port up to a Linux kernel from about 2008.
Not a great result. So, does this Raspberry run a kernel that has and RTAI patch?

I assume not. But, recently, there has been some work on getting EMC2 to run with
a preemp-RT kernel, which should be a lot easier to come by.

Anyway, the OMAP chip on the BeagleBoard has another quirk, the GPIO functions
are multiplexed, so although the CPU runs at 700 MHz, the GPIO is only updated at
4 MHz, creating a bit of a bottleneck. I don't know if all ARMs work this way, but
there are at least rumors that some don't. Otherwise, one might be able to use
one of the serial interfaces that might go a bit faster. However, 8 bits * 4 MHz =
32 mbit/second, so IIC won't really give any boost.

Jon

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16 Aug 2011 02:22 #12515 by PCW
"anyone rekon one of these would run emc2?"

'run' would be a somewhat optimistic term with only 128M of shared RAM
and 700 MHz integer only processor (no hardware floating point)

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16 Aug 2011 03:27 #12516 by jmelson
PCW wrote:

"anyone rekon one of these would run emc2?"

'run' would be a somewhat optimistic term with only 128M of shared RAM
and 700 MHz integer only processor (no hardware floating point)

Oh, that would be a killer! The BeagleBoard has 256M memory (I think) and
hardware FP. It also costs quite a bit more.

Jon

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16 Aug 2011 05:05 #12519 by M4MazakUser
ACTUALLY, there is a 256mb model @$35



Following the example of the BBC Micro, we intend to launch both a Model A device (lacking the LAN9512, and with 128MB of RAM) at the $25 price point, and a Model B device (including the LAN9512, and with 256MB of RAM) for a $5-10 additional cost. We remain confident of shipping before the end of 2011.

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29 Aug 2011 03:00 #12805 by M4MazakUser
btw - just read this.....

It uses an ARM VFP floating point unit (an option when you build an ARM1176).

? does this make it more viable?

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