cschiro
Posts: 1
Joined: Thu Jan 10, 2019 9:02 pm

Interface boards for Quadrature Encoders

Thu Jan 10, 2019 9:20 pm

Hello-
I am a new to this forum and need help to learn if there are hardware interface board(s) for Raspberry PI for interfacing Quadrature Encoders. Specifically,I am looking for a PI interface module that uses LS7267-S 24-bit Dual-Axis Quadrature Counter or similar chip to keep track of the encoder. Details on this chip can be found at https://www.usdigital.com/products/inte ... s/LS7267-S.
I am aware of trying to do this in software but am concerned about keeping up with multiple encoders and seek a interface module to do this work.
Thank You
Craig

ptimlin
Posts: 10
Joined: Tue Jan 08, 2019 7:44 pm

Re: Interface boards for Quadrature Encoders

Sun Jan 13, 2019 3:55 am

You may have to make your own. If prototyping is an issue with the chip you mentioned perhaps something like the old HCTL-2016 might work for you. You will need one per axia and is 16 bit, but comes in a good old protoboard friendly DIP package.

dave j
Posts: 111
Joined: Mon Mar 05, 2012 2:19 pm

Re: Interface boards for Quadrature Encoders

Sun Jan 13, 2019 5:13 pm

If you can't find anything else more suitable, you could consider using an STM32 microcontroller. These are available on a prototyping friendly board very cheaply as blue pills. Many of the timers in these chips have an encoder mode for counting the inputs from a rotary encoder so you could use the timers to record values and transfer them to the Pi using SPI, serial or even USB. Blue pills provide the pins for up to four timers to be used in encoder mode. You can even program them relatively easily Arduino style - see STM32duino.

jdb
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1800
Joined: Thu Jul 11, 2013 2:37 pm

Re: Interface boards for Quadrature Encoders

Thu Jan 17, 2019 9:55 pm

The chip is accessed through a command/address bus with chip-enable and R/W# signalling.

There's the SMI peripheral on the Pi which could be used to interface to this. It would require careful reading of the timings and you will have to munge the address pins on to the various "register select" pins, but it looks doable.

https://github.com/raspberrypi/linux/co ... e30329c1d0
Rockets are loud.
https://astro-pi.org

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