v(k)
+
x(k)
*
x(k
*
1)
T
+
D
X
T
or
∆
X
x(k−1)
∆
T
t(k)
t(k−1)
T
QEPA
QEPB
QCLK
QPOSCNT
UPEVNT
QCTMR
UTOUT
x(k)
Enhanced Quadrature Encoder Pulse (eQEP) Module
Figure 15-145. 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.
1668
Pulse-Width Modulation Subsystem (PWMSS)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated