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.

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

I tried a few "cable typ" adapters over several month and was never successful. With different ssd's and different image writers like etcher...

But also pi 3 is only usb-2 the Pi 3 adapter version of that already is a usb-3 solution. Transferring an image is fasssst. And it started until now all kind of imgs i tried.

PI3-version: The connection between both is only via USB. (small special pcb). And you can connect on the 40 pin two wires to have power via that adapter. Also it is not a must.

Ordered already some of the 4 versions, not having any pi 4 in the moment. Too many projects and rare free time..... ;-(
Mike

Mike_Eitel wrote:

I tried a few "cable typ" adapters over several month and was never successful. With different ssd's and different image writers like etcher...

I've never been able to make etcher work.

But also pi 3 is only usb-2 the Pi 3 adapter version of that already is a usb-3 solution. Transferring an image is fasssst. And it started until now all kind of imgs i tried.

PI3-version: The connection between both is only via USB. (small special pcb). And you can connect on the 40 pin two wires to have power via that adapter. Also it is not a must.

Ordered already some of the 4 versions, not having any pi 4 in the moment. Too many projects and rare free time..... ;-(
Mike

Likewise. Trying to put new fenner belts in my old sheldon, got it apart and my ticker gave me hell despite a pacemaker.
So I basically laying around till my heart doc gets back, supposedly next week.

Belts complicated by finding someone had sprayed metal on the right end of the upper jackshaft to bring it back to size, and that came loose and demolished itself, and the bearings too so I bought a new shaft and should have its bearings today. But did you ever try to cut woodruff key slots in an Rockwell 60C shaft? Got something usable but it ain't purty.
Tried to EDM it but a carbide tool for the electrode went away lots faster than the slot was burnt. Finally mounted it onto my 6040 mill where I had a rotary table so I could turn the shaft a couple degrees each way to try and grind a slot the same width all the way to the bottom using dremel 3/4" cutoff wheels stacked 4 wide. Slow, and definitely not fun.

The middle key slot is optional as I've already fitted a taperlock in the pulley bore which was wallered out 20 thou oversize two years ago. 70 yo lathe. A pi3b runs it fairly well though

And I am not going to exert myself too much putting it back together until I can do it w/o the angina pain. I don't recommend getting old. Its not for wimps.

Take care now Mike.

OT:
Me. Still healthy but with 62..... You never know....
Best health Gene

True, but at 62 you're still as good as you were, once. Check back in 22 more years.