I actually saw a youtube video where someone was using this chip.  I believe he said it was like $28, and you'd still need something to read/run

it with. (also,  not running linux cnc on the pi,  the little raspberry pi project has nothing to do with my linux cnc machine, I just did that to read

the quadrature encoder.


Here's the video I found a while back: https://www.youtube.com/watch?v=RLCPKa9SoF0


Ron

On 5/25/20 1:35 AM, John Dammeyer wrote:
BTW,  Check out
https://lsicsi.com/datasheets/LS7366R.pdf
This device is interfaced via SPI and has a 32 bit quadrature counter module.  
If you go in the direction of Raspberry Pi with LinuxCNC a device like this can 
provide the spindle information.  So if someone was thinking of building a CNC 
cape for a Pi a device like this would be a good idea.  There are also devices 
from the same manufacturer that can change quadrature into up/down pulses 
streams to use regular counters inside the Pi.

John


-----Original Message-----
From: R C [mailto:[email protected]]
Sent: May-24-20 6:01 PM
To: linuxcnc-users-list
Subject: Re: [Emc-users] Encoder HAL programming.


On 5/24/20 6:29 PM, andy pugh wrote:
On Mon, 25 May 2020 at 00:17, R C <[email protected]> wrote:

I have been following this thread.  I wrote some code that runs on an
RPI that can read a quadrature encoder, I have a few of them, with
different resolutions.
Is this something different to the normal LinuxCNC software encoder
that reads GPIO?
Is there some dedicated encoder counter hardware on the Pi?

Oh I am not running linux cnc on an rpi, I run it on a server "class"
machine.�� I was just curious about how these encoders work, and why
they didn't

work that well with my linux-cnc setup using a db25 BOB with the 2
benchtops I have.


So I decided to use an RPI (because it is easy to use GPIO pins to read
signals) and write some code to read these� encoder signals.



So I guess my answer is yes,� it is different from, what linux-cnc
running on a pi does (I would be surprised if it was similar)


I setup an RPI, hooked up a 2 line LCD display to it to display rpms,
wrote some interrupt driven code that reads the encoder and displays it
on the LCD. The idea is, I want

to try and see if I can read the encoder and then send signals back to
linux-cnc that it 'could handle".


So I have a 60ppr encoder,� 60 has a lot of dividers.� 2, 3, 4, 5, 6,
10, and 12� So if I can "transfer" a pulse with a consistent delay
exactly when the actual n-th pulse

comes in, I could turn a 60ppr� encoder into a 30, 20, 15, 12, 10, 6 or
5 ppr encoder by just skipping pulses,� while raising some GPIO pins,
that I connect to the BOB, when

I read a different set of GPIO pins directly from the encoder.



But as I said earlier,� I don't know a lot about the linux-cnc's
internals, and HAL, but it is something I am playing with to see if it
could work.


Ron



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