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PiCAT Xenomai 3 for Raspberry pi 4

PiCAT Xenomai 3 for Raspberry pi 4

bruno

Published June 08, 2021

190 UCC

15 WCC

41 VAR

1 Followers

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Project description

Prepare Xenomai 3 kernel

EtherCAT master

Get source code and example
git clone -b rpi4-xenomai-3 git://github.com/thanhtamh/soem-w5500-rpi.git
cd soem-w5500-rpi
chmod +x *.sh
./build.sh
And test
cd test/slaveInfo/
sudo ./slaveinfo wiz -map

Important notes

EtherCAT Master has been updated to SOEM 1.4.0. A full list of new features can be found at SOEM document link:?https://openethercatsociety.github.io/doc/soem/
Note on SPI speed: The SPI bit rate is divided from GPU core frequency. For previous Raspberry pi revisions (0,1,2,3) the default core frequency is 250 Mhz. Therefore a divider of 16 will provide the spi speed of 15.625 Mhz.
wiznet_hw_config(16, 0, 0); //15.625 Mhz on previous rpi versions
With Raspberry pi 4, default? core frequency is 500 Mhz, with the same divider value, spi speed is 2 times faster, e.i.?a divider of 16 will provide the spi speed of 31.25 Mhz. 
wiznet_hw_config(16, 0, 0); //31.25 Mhz on rpi4
GPU core frequency is a dynamic quantity, it can vary depending on system load, in order to prevent spi speed change during operation we can simply fix?GPU core frequency by setting in /boot/config.txt file: core_freq_min=500 core_freq=500
Posted?16th June 2020?by?Ho Tam

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