Quadrature sensor not working when plugged in cortex port 4

VEX V5 General Discussion Technical Discussion
1

I have three quadrature encoders plugged into the cortex, and 11 out of the 12 digital ports are being used. When I plug these quad encoders into different ports and ‘open debugger manually’ in robotC to view sensor values, the encoder which has a wire plugged into port 4 can have invalid values of -1, 0 or 1.

Here are the steps to reproduce the error.

  1. Plug the three encoders in port 1&2, 3&4, 5&6, the middle one works some time, but no longer working after a cortex restart.
  2. Change them to 1&2, 4&5, 7&8, the middle one will always give values of -1, 0 or 1

Finally I plug these encoders in port 1&2, 5&6, 7&8, now they are working properly.

The Attached files shows the setup of the robot. I am using the latest robotC 4.30 and updated to the latest cortex firmware.

Is this a bug or feature in robotC or the VEX cortex?

http://postimg.org/image/ijqmfsg75/
http://postimg.org/image/oxlymb1tb/
http://postimg.org/image/8oupfn0eh/
quad3.jpg
quad2.jpg
quad1.jpg

2

There’s an issue with the cortex involving port 4 and port 10.

See this.
https://vexforum.com/showpost.php?p=325870&postcount=3
and this.
https://vexforum.com/showpost.php?p=314422&postcount=6

Try and avoid using port 10 as an output and you should be ok (it’s hard to see your images, they are too small or I would suggest a setup that would work).

3

Thanks for your prompt reply! I re-posted the images and hope you can now see the images…