Raspberry Pi 4

Please no more *duinos, maybe a nice ST STM32 or NXP LPCxxxx

So you are toggling the GPIO's at:
High ..... Low .......Complete Cycle
80uS + 80uS = 160uS = 6,250.0Hz
80uS + 160uS = 240uS = 4,166.7Hz
80uS + 240uS = 320uS = 3,125.0Hz
80uS + 320uS = 400uS = 2,500.0Hz

> maybe a nice ST STM32

I've tried a ST32 H743ZI nucleo board with step-pulses sent by
raw-eth.
but the IP-stack needs a lot of overhead - and problem of the PI4
timing is the same as above.
I think, stepper-signal generation I must be done by external hardware...
the PI4/RT-kernel are too slow (for a squarewave above 2kHz)

or in a closed-loop with stepper/rotary-encoder a PI4 should work.

Latest from RealtimePi:

Ok, unmouinting the docker environment and remounting fixed it. Strange but fixed

Image:
unofficialpi.org/Distros/RealtimePi/nigh...uster-lite-0.4.0.zip
md5:
unofficialpi.org/Distros/RealtimePi/nigh...r-lite-0.4.0.zip.md5

kernel only that you can untar on top of an existing raspbian:
unofficialpi.org/Distros/RealtimePi/nigh...ernel-4.19.59.tar.gz

Note: I didn't change the cmdline.txt mentioned here:
raspberrypi/linux#2943 (comment)
Likely now that the usd owc patch is in place I can remove that, rebuild, and hopefully release.

andypugh wrote: Latest from RealtimePi:

Ok, unmouinting the docker environment and remounting fixed it. Strange but fixed

Image:
unofficialpi.org/Distros/RealtimePi/nigh...uster-lite-0.4.0.zip
md5:
unofficialpi.org/Distros/RealtimePi/nigh...r-lite-0.4.0.zip.md5

kernel only that you can untar on top of an existing raspbian:
unofficialpi.org/Distros/RealtimePi/nigh...ernel-4.19.59.tar.gz

From Gene:
Will this run on a pi3b? And does it use the new video drivers raspian is now using w/o the realtime kernel?
I have a 2G pi4 coming, and there were patches for rpspi back up the line if I can get them. I'd like to try the 3 before rebuilding my setup for the 4.

Note: I didn't change the cmdline.txt mentioned here:
raspberrypi/linux#2943 (comment)
Likely now that the usd owc patch is in place I can remove that, rebuild, and hopefully release.

Not jet supported but used in pi 3 version very successfully :
Expansion board to start and run from normal ssd. Much faster and no shdc dying sooner or later. New version also order able on aliexpress.

geekworm.com/products/raspberry-pi-4-mod...-ssd-expansion-board

m5c
Mike

Mike_Eitel wrote: Not jet supported but used in pi 3 version very successfully :
Expansion board to start and run from normal ssd. Much faster and no shdc dying sooner or later. New version also order able on aliexpress.

geekworm.com/products/raspberry-pi-4-mod...-ssd-expansion-board
Thats cute, but interferes with my present spi setup, requiring a make a cable about 2" longer. I already have usb-3 to sata cables that work on a pi's usb-2.

Thanks for the update, I am glad to see such progress being made for the pi-4.

m5c
Mike