Breakouts

Sub forum for Parallella daughter cards and accessories

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Re: Breakouts

Postby 9600 » Wed Feb 19, 2014 7:52 am

MfA wrote:I'd like to see some fast I/O broken out on convenient connectors as well, SATA connectors for instance.


Nice idea! And a daughter card to do this shouldn't be too difficult to make...

Cheers,

Andrew
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Re: Breakouts

Postby MfA » Wed Feb 19, 2014 4:41 pm

Can't claim the idea as my own, saw it on Dan Strother's website ... who unfortunately seems to have gone underground.

http://danstrother.com/2011/01/16/spart ... est-board/
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Re: Breakouts

Postby frank_buss » Thu Jun 19, 2014 1:36 am

I designed a simple GPIO breakout board:

Image

It is the second revision, I should get it next week. The first revision had only one Samtek connector, but this is not very stable (and I used the wrong distance, so I can't plugin both sides in my breadboard). But is still usable for testing the GPIO pins (on PEC_FPGA). This is the test setup:

Image

The idea is to use it as a raw breakout board for both sides: The Samtek connector footprint on my board has 4 holes, so it can be soldered 180° rotated, if you need it for PEC_NORTH and PEC_SOUTH. The distance between the header pins fits into my two row breadboard, so I can use all GPIO pins and all PEC_POWER pins.

I found no information about how to use it from Linux. I installed the latest Linux kernel and FPGA bitstream with HDMI support for my 16-core / Zync 7020 board, then I just wrote a bash script to test all GPIO pins and with binary searching I found it quickly. First a copy of the drawing from the Parallella reference manual, with additional pin numbering for the GPIO pins, as I understand it from the Samtek datasheet:

Image

Now the mapping:





SignalPEC_FPGA pinLinux GPIOJ2 pinJ3 pin
GPIO0_N35429
GPIO1_N45529
GPIO0_P55628
GPIO1_P65728


J2 and J3 are the two pin headers on my breakout board.

To use it, login to the system with "linaro" (same password, possible over SSH, too) and switch to root user with "sudo su". Then enter this:

Code: Select all
echo 54 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio54/direction
echo 1 > /sys/class/gpio/gpio54/value


and the PEC_FPGA pin 3 should go high. Use "echo 0 > /sys/class/gpio/gpio54/value" to switch it to low.

A page like http://elinux.org/RPi_Low-level_peripherals would be nice for the GPIO pins. I can finish the drawing and table I've started, if someone is interested in it and if it doesn't exists already.
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Re: Breakouts

Postby AndyC » Wed Sep 10, 2014 2:35 pm

Hi Frank,

Do you have that table, I would be very interested in it.

Cheers

Andy
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