[eQEP] Position Counter Reset on the First Index Event - which edge?

Pascal53023

Other Parts Discussed in Thread: TMS320F28335

Hello,

I am using the EQEP module of the TMS320F28335 with an quadrature encoder. The position counter has to be resetted on the first index event. The eQEP ref. manual says in chapter 4.1.3.

"If the index event occurs during forward movement, then the position counter is reset to 0 on the next eQEP clock."

What is the index event? The rising or the falling edge of the index impulse?

over 15 years ago

0 Arefeen over 15 years ago

Genius 5170 points

I believe Index Event can be configured as a rising edge or a falling edge.

0 Pascal53023 over 15 years ago in reply to Arefeen

Prodigy 90 points

Thank you for your answer. I searched the whole eQEP Reference Guide for "index event", but I only found an option to negate the Index-Input in the eQEP Decoder Control (QDECCTL) Register: QIP (QEPI input polarity). That doesnt help me considering which edge of the index impulse triggers the index "event" :-/

0 Arefeen over 15 years ago in reply to Pascal53023

Genius 5170 points

I agree with you ... the documentation is not clear on this or at least I couldn't find a clear description. May be TI folks will clarify what is meant by "Index Event" or for a quicker response you may also try TI hot line.

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[eQEP] Position Counter Reset on the First Index Event - which edge?