QFLG:UTO
QUPRD
32
QUTMR
32
QEPCTL:UTE
UTIME
SYSCLKOUT
UTOUT
QFLG:WTO
QWDPRD
16
QWDTMR
16
QEPCTL:WDE
QWDOG
RESET
SYSCLKOUT
/64
SYSCLKOUT
QCLK
WDTOUT
eQEP Watchdog
839
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Enhanced QEP (eQEP) Module
Parameter
Relevant Register to Configure or Read the Information
T
Unit Period Register (QUPRD)
Δ
X
Incremental Position = QPOSLAT(k) - QPOSLAT(K-1)
X
Fixed unit position defined by sensor resolution and ZCAPCTL[UPPS] bits
Δ
T
Capture Period Latch (QCPRDLAT)
9.6
eQEP Watchdog
The eQEP peripheral contains a 16-bit watchdog timer that monitors the quadrature-clock to indicate
proper operation of the motion-control system. The eQEP watchdog timer is clocked from
SYSCLKOUT/64 and the quadrate clock event (pulse) resets the watchdog timer. If no quadrature-clock
event is detected until a period match (QWDPRD = QWDTMR), then the watchdog timer will time out and
the watchdog interrupt flag will be set (QFLG[WTO]). The time-out value is programmable through the
watchdog period register (QWDPRD).
Figure 9-18. eQEP Watchdog Timer
9.7
Unit Timer Base
The eQEP peripheral includes a 32-bit timer (QUTMR) that is clocked by SYSCLKOUT to generate
periodic interrupts for velocity calculations. The unit time out interrupt is set (QFLG[UTO]) when the unit
timer (QUTMR) matches the unit period register (QUPRD).
The eQEP peripheral can be configured to latch the position counter, capture timer, and capture period
values on a unit time out event so that latched values are used for velocity calculation as described in
Section
Figure 9-19. eQEP Unit Time Base