DIR
QPOSCMP
QPOSCNT
PCSOUT (active HIGH)
PCSPW
PCSPW
PCSPW
PCEVNT
POSCMP=2
0
1
2
3
4
3
2
1
0
1
2
3
4
3
2
1
0
eQEP counter
PCEVNT
PCSOUT (active HIGH)
PCSOUT (active LOW)
PCSPW
Enhanced Quadrature Encoder Pulse (eQEP) Module
The position-compare match (QFLG[PCM]) is set when the position-counter value (QPOSCNT) matches
with the active position-compare register (QPOSCMP) and the position-compare sync output of the
programmable pulse width is generated on compare match to trigger an external device.
For example, if QPOSCMP = 2, the position-compare unit generates a position-compare event on 1 to 2
transitions of the eQEP position counter for forward counting direction and on 3 to 2 transitions of the
eQEP position counter for reverse counting direction (see
shows the layout of the eQEP Position-Compare Control Register (QPOSCTL) and
describes the QPOSCTL bit fields.
Figure 15-141. eQEP Position-compare Event Generation Points
The pulse stretcher logic in the position-compare unit generates a programmable position-compare sync
pulse output on the position-compare match. In the event of a new position-compare match while a
previous position-compare pulse is still active, then the pulse stretcher generates a pulse of specified
duration from the new position-compare event as shown in
.
Figure 15-142. eQEP Position-compare Sync Output Pulse Stretcher
1665
SPRUH73H – October 2011 – Revised April 2013
Pulse-Width Modulation Subsystem (PWMSS)
Copyright © 2011–2013, Texas Instruments Incorporated