Minimum eQEP usage in ARM335x

Lukasz Przenioslo

Hello there,

I am designing a BeagleBone Black application. I need to count pulses from a motor driver. For that purpose I wanted to use the eQEP module. My problem is that I need every GPIO possible on the board. So I was wondering either the eQEP module would still work if I only use the input eQEP_A and use eQEP_B for other purpose, without biasing it to VCC/2.

Can eQEP module be configured in software like that?

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

You will lose direction information. I don't know where you found the information that eQEP_B can be biased to VCC/2 - this is a digital input that normally receives a signal that's dephased by 90^o from eQEP_A. See AM335X TRM Rev. K section 15.4.

0 Lukasz Przenioslo over 11 years ago in reply to Biser Gatchev-XID

Expert 2630 points

Ignore the VCC biasing... I thought of something else. You are right, I will loose direction, but I dont need it. I only need to receive one quadrature signal. Can in that case eQEP_A be used and eQEP_B be used for other gpio purposes?

0 Biser Gatchev-XID over 11 years ago in reply to Lukasz Przenioslo

TI__Guru**** 393215 points

If you look at Figure 15-134 you will see that eQEP_A can be directly routed to QCLK, while QDIR can be sourced from eQEP_B, or tied to a fixed level of 0/1. This will be Up-Count Mode (section 15.4.2.3.1.3) or Down-Count Mode (section 15.4.2.3.1.4).

0 Lukasz Przenioslo over 11 years ago in reply to Biser Gatchev-XID

Expert 2630 points

I see, that means it is possible I gues. Thank you for help.

(Please verify my question clearly- yes or no)

Processors

Processors forum

Minimum eQEP usage in ARM335x