Russ Ether

interfacing MC9S08DZ60 to Hall sensors

Discussion created by Russ Ether on Nov 21, 2006
Latest reply on Nov 21, 2006 by Mark Hotchkiss
What's the best way to interface the MC9S08DZ60 to Hall sensors (to commutate a brushless DC motor) ?
I need to detect the change in the Hall sensor output in both directions, so I need to detect (and interrupt on) both rising and falling edges.
As I read the data sheet, GPIO pins can be configured to detect either rising or falling, but not both.
Is it OK to tie 2 GPIO pins together, and configure one for rising and the other for falling?  That would generate 2 separate interrupts for each Hall sensor, but that's OK - I could just set a flag to indicate which interrupt is being serviced and call a common routine.
Is there a better way to do this that I am missing? 
I thought about using a TPM channel as input capture (since that can be configured to interrupt on both edges) but all the TPM channels are being used.
Thank you.