Position Counter Underflow/Overflow (Qposmax = 4) - Texas Instruments Concerto F28M35 Series Technical Reference Manual

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Figure 9-9. Position Counter Underflow/Overflow (QPOSMAX = 4)

Position Counter Reset on the First Index Event (QEPCTL[PCRM] = 10)

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

eQEP clock. If the index event occurs during the reverse movement, then the position counter is reset to

the value in the QPOSMAX register on the next eQEP clock. Note that this is done only on the first

occurrence and subsequently the position counter value is not reset on an index event; rather, it is reset

based on maximum position as described in Section

The first index marker fields (QEPSTS[FIDF] and QEPSTS[FIMF]) are not applicable in this mode.

Position Counter Reset on Unit Time out Event (QEPCTL[PCRM] = 11)

In this mode, the QPOSCNT value is latched to the QPOSLAT register and then the QPOSCNT is reset

(to 0 or QPOSMAX, depending on the direction mode selected by QDECCTL[QSRC] bits on a unit time

event). This is useful for frequency measurement.

9.4.2 Position Counter Latch

The eQEP index and strobe input can be configured to latch the position counter (QPOSCNT) into

QPOSILAT and QPOSSLAT, respectively, on occurrence of a definite event on these pins.

SPRUH22I – April 2012 – Revised November 2019

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Position Counter and Control Unit (PCCU)

C28 Enhanced QEP (eQEP) Module

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