Registers
755
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Enhanced Pulse Width Modulator (ePWM) Module
Table 7-54. Dead-Band Generator Control Register (DBCTL) Field Descriptions (continued)
Bit
Field
Value
Description
9-8
LOADFEDMODE
Active DBFED Load from Shadow Select Mode
00
Load on CTR = 0
01
Load on CTR = PRD
10
Load on either CTR = 0 , or CTR = PRD
11
Freeze (no loads possible)
Note: has no effect in Immediate mode.
7-6
LOADREDMODE
Active DBRED Load from Shadow Select Mode
00
Load on Counter = 0 (CNT_eq)
01
Load on Counter = Period (PRD_eq)
10
Load on either Counter = 0, or Counter = Period
11
Freeze (no loads possible)
Note: has no effect in Immediate mode.
5-4
IN_MODE
Dead-Band Input Mode Control
Bit 5 controls the S5 switch and bit 4 controls the S4 switch shown in
This allows you to select the input source to the falling-edge and rising-edge delay.
To produce classical dead-band waveforms the default is EPWMxA In is the source for
both falling and rising-edge delays.
00
EPWMxA In (from the action-qualifier) is the source for both falling-edge and rising-edge
delay.
01
EPWMxB In (from the action-qualifier) is the source for rising-edge delayed signal.
EPWMxA In (from the action-qualifier) is the source for falling-edge delayed signal.
10
EPWMxA In (from the action-qualifier) is the source for rising-edge delayed signal.
EPWMxB In (from the action-qualifier) is the source for falling-edge delayed signal.
11
EPWMxB In (from the action-qualifier) is the source for both rising-edge delay and falling-
edge delayed signal.
3-2
POLSEL
Polarity Select Control
Bit 3 controls the S3 switch and bit 2 controls the S2 switch shown in
This allows you to selectively invert one of the delayed signals before it is sent out of the
dead-band submodule.
The following descriptions correspond to classical upper/lower switch control as found in
one leg of a digital motor control inverter.
These assume that DBCTL[OUT_MODE] = 1,1 and DBCTL[IN_MODE] = 0,0. Other
enhanced modes are also possible, but not regarded as typical usage modes.
00
Active high (AH) mode. Neither EPWMxA nor EPWMxB is inverted (default).
01
Active low complementary (ALC) mode. EPWMxA is inverted.
10
Active high complementary (AHC). EPWMxB is inverted.
11
Active low (AL) mode. Both EPWMxA and EPWMxB are inverted.
1-0
OUT_MODE
Dead-Band Output Mode Control
Bit 1 controls the S1 switch and bit 0 controls the S0 switch shown in
00
DBM is fully disabled or by-passed. In this mode the POLSEL and IN-MODE bits have no
effect.
01
Apath = InA (delay is by-passed for A signal path)
Bpath = FED (Falling Edge Delay in B signal path)
10
Apath = RED (Rising Edge Delay in A signal path)
Bpath = InB (delay is by-passed for B signal path)
11
DBM is fully enabled (i.e. both RED and FED active)