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:cjv...@gmail.com] > 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 <cjv...@gmail.com> 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 > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
