Raspberry Pi 4 mmap

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13 Jan 2021 04:52 - 13 Jan 2021 05:05 #195172 by tjtr33
Replied by tjtr33 on topic Raspberry Pi 4
@ Bari
i did not try raising servo thread ( 1000us to 2000us)
Same base but servo at 1000 was _not_ 50uS or less, so ,
Thx for the idea. tomp
Last edit: 13 Jan 2021 05:05 by tjtr33.

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18 Jan 2021 05:25 - 18 Jan 2021 05:35 #195750 by tjtr33
Replied by tjtr33 on topic Raspberry Pi 4
re 2000uS servo thread
I have success with soft stepper 75uS base 1000uS servo
but latency is too bad with servo 2000, so
my best effort is 75uSbase 1000 servo. My 1.5mm screw and 200 setp/rev
motors gets me 50 steps/sec 3meters per min without doublestep.
I am working on hal_pi_gpio to get inverted pins and reset pins.
That woul allow my RPi3 6meters /min software stepping.
Its reliable, I have been running a 3Dchips modified to loop 100 times. Its run many times now over 3 days, no UXRTdelays.

tomp
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Last edit: 18 Jan 2021 05:35 by tjtr33. Reason: add screenshot
The following user(s) said Thank You: Mike_Eitel

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18 Jan 2021 07:10 - 18 Jan 2021 07:12 #195755 by tjtr33
Replied by tjtr33 on topic Raspberry Pi 4 mmap
Hello Andy
re: #158377
I have been studying hal_parport hal_pi_gpio and opi_gpio
to see how gpio drivers handle user instancing and
how the program stores the states of pins.

I am headed down this road:
loadrt hal_pi_gpio \
  dir=0,0,0,0,0,0,0,0,0,1,0,0,1,1,0,1,0,0,0,0,0,0,0,1,1,1 \
  exc=0,1,1,1,1,1,0,1,1,0,0,1,0,0,1,0,1,1,1,1,1,1,1,0,0,0 \
  rst=0,0,0,0,0,0,0,0,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0

That would create 3 32bit stores , one each for direction, exclusion, and reset-ability.

I have no provision for pullup pull down or open collector/tristate ,
because I think users can use external resistors as they like
and I avoid the OC issue due to cowardice. ( not important imo ).

So, instead of the trplets stored right now describing 10pins , inside 3 32bit memories
there would be simpler 3 32 bit-fields describing the 3 features
very easy to see with a fixed font.

Also I will add the missing invert pins to all inputs in the dir parm.

any thoughts?
thx
Tomp
Last edit: 18 Jan 2021 07:12 by tjtr33.

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18 Jan 2021 21:14 #195833 by andypugh
Replied by andypugh on topic Raspberry Pi 4 mmap
How about a single 32 element string, containing letters? R = output / reset I = in, O = out...

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06 Feb 2021 23:36 - 06 Feb 2021 23:40 #197882 by The Feral Engineer
New to the pi game. Just got it installed yesterday. Had a runaway today testing different isolcpus. It was on the default 3 from the 2.8.1 /iso installer file and when I went to jog Z, it kept going until I killed everything. I get constant runaways with my touch screen as well - planar pct2235. Screen works a treat on my 12 year old pc running my router (deb10, 2.8.1, g540). I should mention that the runaway I'm most concerned about was jogging with the keyboard.

With the touchscreen, I'm sure it's a pi driver issue as nothing works reliably (other apps like onboard or just general navigating) but it works great hooked to my other computer. This machine is an emco pc turn 55 with 7i76ed and pi4b.

Also pretty interested in if there are benefits to the 7c80 vs 7i76e/ed with pi?
Last edit: 06 Feb 2021 23:40 by The Feral Engineer.

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07 Feb 2021 00:16 #197884 by PCW
Replied by PCW on topic Raspberry Pi 4 mmap
Main benefits are that you retain your Ethernet port
and the 1 KHZ servo threads are possible

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07 Feb 2021 01:05 #197886 by The Feral Engineer

Main benefits are that you retain your Ethernet port
and the 1 KHZ servo threads are possible


What does the pi/7i76 combo servo thread cap out at? Kinda wish i knew about the 7c81 before ordering those 7i76ed cards, but the pi was an afterthought. I originally wanted to run from a micro pc (u700) but that failed hard (400k latency) :lol:

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07 Feb 2021 01:30 #197887 by andypugh
Replied by andypugh on topic Raspberry Pi 4 mmap

New to the pi game. Just got it installed yesterday. Had a runaway today testing different isolcpus. It was on the default 3 from the 2.8.1 /iso installer file and when I went to jog Z, it kept going until I killed everything


How were you jogging? MPG? HAL pins? Keyboard? Joypad?

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07 Feb 2021 01:33 #197888 by The Feral Engineer

New to the pi game. Just got it installed yesterday. Had a runaway today testing different isolcpus. It was on the default 3 from the 2.8.1 /iso installer file and when I went to jog Z, it kept going until I killed everything


How were you jogging? MPG? HAL pins? Keyboard? Joypad?


I'm getting runaways with the touch screen and the one that scared me most was the keyboard. I'll try and replicate it tomorrow

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07 Feb 2021 12:29 #197911 by andypugh
Replied by andypugh on topic Raspberry Pi 4 mmap
That sounds like the system isn't receiving keyup events, for some reason.

Keyboard jogging should only go as far as the axis limits, but that is not much of a safety net if you are jogging Z down.

FWIW I don't trust USB / GUI for jogging any of my machines. It's much more dependable to jog via HAL pins, for example with an MPG.
I have never seen the problems you have, but I am aware of the possibility.

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