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
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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 Figure 15-141).
Figure 15-163 shows the layout of the eQEP Position-Compare Control Register (QPOSCTL) and
Table 15-138 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.
Figure 15-142. eQEP Position-compare Sync Output Pulse Stretcher
1665
SPRUH73H–October 2011–Revised April 2013 Pulse-Width Modulation Subsystem (PWMSS)
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