v(k)
+
x(k)
*
x(k
*
1)
T
+
D
X
T
o
∆
X
x(k−1)
∆
T
t(k)
t(k−1)
T
QEPA
QEPB
QCLK
QPOSCNT
UPEVNT
QCTMR
UTOUT
x(k)
eQEP Edge Capture Unit
838
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Enhanced QEP (eQEP) Module
Figure 9-17. eQEP Edge Capture Unit - Timing Details
Velocity Calculation Equations:
(4)
where
v(k): Velocity at time instant k
x(k): Position at time instant k
x(k-1): Position at time instant k-1
T: Fixed unit time or inverse of velocity calculation rate
Δ
X: Incremental position movement in unit time
X: Fixed unit position
Δ
T: Incremental time elapsed for unit position movement
t(k): Time instant "k"
t(k-1): Time instant "k-1"
Unit time (T) and unit period(X) are configured using the QUPRD and QCAPCTL[UPPS] registers.
Incremental position output and incremental time output is available in the QPOSLAT and QCPRDLAT
registers.
