AVR-Chat

I do this often.  Check out www.barello.net/Papers (motion control),
www.barello.net/ARC (look at sample code & projects), and
www.barello.net/Robots.

The Schmitt trigger inputs on all AVR's conditions the raw opto output.
Depending upon speed of the count you can either poll or use interrupts.  If
the count rate (edge rate) is less than 5k/second or so, I would poll: set
up a 10khz timer interrupt that examines the inputs and increments a counter
with each transition (low->high, high->low).  Greater than 10k edges/sec I
would use one of the edge sensitive interrupts (INT0, 1, ACD, ICP) and then
switch edge sense within you handler (e.g. after a positive edge, switch to
negative, and so forth).

Then in your main loop, examine and clear the counter periodically to get
velocity.

Using the hardware counter would have very low software overhead and would
be best for count rates >100k/sec, but there is only one of those in the AVR
so I have never used it (I always handle two channels of two lines/encoder
so I need four interrupts).

Cheers!
-----Original Message-----
From: Ridho Alpha [mailto:pendekar_ridho@yahoo.com]
Sent: Sunday, January 09, 2005 9:03 AM
To: AVR-Chat@yahoogroups.com
Subject: [QUARANTINE][AVR-Chat] asking about encoder..external interrupts or
counter???


hello
i use AVR for motor control, I use ATMEGA16. i ask for encoder which is made
just from optocoupler "U" model.the output is pulses. What do you think how
i can read the counter???counting process.the best solution?? Using External
Interrupt?? Using Counter??? please give a clue....

thank you
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