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nerd7473
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Raspberry Pi, GPIO, and other CPUs

Fri Mar 14, 2014 6:03 pm

I need to know if the pi can hook to an GPIO expansion board and then to some sort of circuit to control another processor to give the Pi more processing power. Also would like to know if there are more single board PCs that could accomplish this feat.
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FLYFISH TECHNOLOGIES
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Re: Raspberry Pi, GPIO, and other CPUs

Fri Mar 14, 2014 6:15 pm

Hi,
nerd7473 wrote: control another processor to give the Pi more processing power.
A solution that comes to my mind is to use several RasPis networked together (Ethernet).

Various boards with some processors (microcontrollers) could be attached to GPIO, but generally speaking, this hardware doesn't have significant generic processing power that could be compared to RasPi's one. I'd say that various add-on boards could be used well for some specific tasks (eg. if you need precise timing for stepper motors control, to provide more input/output pins, etc), but I'd not go into this direction for increasing the overall processing power.

If you can tell us more about the use case, you could get more applicable responses.


Best wishes, Ivan Zilic.
Running out of GPIO pins and/or need to read analog values?
Solution: http://www.flyfish-tech.com/FF32

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nerd7473
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Re: Raspberry Pi, GPIO, and other CPUs

Fri Mar 14, 2014 6:25 pm

FLYFISH TECHNOLOGIES wrote:Hi,
nerd7473 wrote: control another processor to give the Pi more processing power.
A solution that comes to my mind is to use several RasPis networked together (Ethernet).

Various boards with some processors (microcontrollers) could be attached to GPIO, but generally speaking, this hardware doesn't have significant generic processing power that could be compared to RasPi's one. I'd say that various add-on boards could be used well for some specific tasks (eg. if you need precise timing for stepper motors control, to provide more input/output pins, etc), but I'd not go into this direction for increasing the overall processing power.

If you can tell us more about the use case, you could get more applicable responses.


Best wishes, Ivan Zilic.

I would love to just make a add on board for the Pi to hook to another CPU perhaps a ARM. I would love to see this work all I am trying to say is I would like to have it be programmed to communicate to the other CPU so I could increase power and decrease CPU usage of the main one.
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Re: Raspberry Pi, GPIO, and other CPUs

Fri Mar 14, 2014 6:44 pm

Almost an impossible proposition! The only "High speed" connection the PI has is USB (and through USB Ethernet).
None of the PI's GPIO interfaces really provides enough throughput to provide fast enough data interchange with another CPU to create a workable DUAL-CPU system. The SPI interface is the only one that comes somewhat close, but the speed you get is more comparable to reading/writing to the SD-card than to external RAM, like you would need with a DUAL-CPU setup.

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nerd7473
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Re: Raspberry Pi, GPIO, and other CPUs

Fri Mar 14, 2014 8:09 pm

mahjongg wrote:Almost an impossible proposition! The only "High speed" connection the PI has is USB (and through USB Ethernet).
None of the PI's GPIO interfaces really provides enough throughput to provide fast enough data interchange with another CPU to create a workable DUAL-CPU system. The SPI interface is the only one that comes somewhat close, but the speed you get is more comparable to reading/writing to the SD-card than to external RAM, like you would need with a DUAL-CPU setup.
sad I wish that it could be possible is it possible with another single board computer
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Re: Raspberry Pi, GPIO, and other CPUs

Fri Mar 14, 2014 8:30 pm

No.

Just buy a more powerful single board computer.

For a lot more than $35
nerd7473 wrote:
mahjongg wrote:Almost an impossible proposition! The only "High speed" connection the PI has is USB (and through USB Ethernet).
None of the PI's GPIO interfaces really provides enough throughput to provide fast enough data interchange with another CPU to create a workable DUAL-CPU system. The SPI interface is the only one that comes somewhat close, but the speed you get is more comparable to reading/writing to the SD-card than to external RAM, like you would need with a DUAL-CPU setup.
sad I wish that it could be possible is it possible with another single board computer
http://Mikronauts.com - home of EZasPi, RoboPi, Pi Rtc Dio and Pi Jumper @Mikronauts on Twitter
Advanced Robotics, I/O expansion and prototyping boards for the Raspberry Pi

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mahjongg
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Re: Raspberry Pi, GPIO, and other CPUs

Fri Mar 14, 2014 11:50 pm

I guess the PI could be used as the "Graphics output device" for a far more powerful ARM based system, as in fact the PI is mostly a GPU with a small CPU tacked on, but its USB "pipeline" may become a bottleneck, I doubt its fast enough to transfer live vide signals through it. Then again you could send it Open GL ES 2.0 commands, and/or H.264 Video to be processed by the PI's GPU.

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Re: Raspberry Pi, GPIO, and other CPUs

Sat Mar 15, 2014 12:45 am

mahjongg wrote:I guess the PI could be used as the "Graphics output device" for a far more powerful ARM based system, as in fact the PI is mostly a GPU with a small CPU tacked on, but its USB "pipeline" may become a bottleneck, I doubt its fast enough to transfer live vide signals through it. Then again you could send it Open GL ES 2.0 commands, and/or H.264 Video to be processed by the PI's GPU.
I need you to explain that because I am a little confused
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Re: Raspberry Pi, GPIO, and other CPUs

Sat Mar 15, 2014 2:28 pm

you could use the PI as a display device for another ARM based computer, so that the PI does all the display tasks. As the speed of the connection between the main board will probably be limited (to the speed of the PI's Ethernet connection, which in turn is limited by the PI's USB system) it will probably be important to "compress" this data when you have to send large amounts of data over it, if sending for example video you do not send over the raw image data, but a H.264 compressed video stream, and let the PI do the decoding. For 3D games too, you do not send decoded 3D images to the PI, but simply the Open GL ES 2.0 commands to draw the screen. The X window system can use the PI as an X client, controlled remotely from the x server running on the fast main system. So basically the PI becomes a Smart Terminal and I/O processor for the main system. Also handling mouse and keyboard I/O (and whatever else USB I/O is needed). The main system then simply consists of a fast ARM processor, with lots of RAM and storage, running its own copy of Linux, but with no I/O at all except for an ethernet connection to the PI.

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