ePWM Registers
2077
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
Enhanced Pulse Width Modulator (ePWM) Module
35.4.2.3 Counter-Compare B Register (CMPB)
Figure 35-70. Counter-Compare B Register (CMPB) [offset = 16h]
15
0
CMPB
R/W-0
LEGEND: R/W = Read/Write; -
n
= value after reset
Table 35-30. Counter-Compare B Register (CMPB) Field Descriptions
Bits
Name
Description
15-0
CMPB
The value in the active CMPB register is continuously compared to the time-base counter (TBCTR). When
the values are equal, the counter-compare module generates a "time-base counter equal to counter
compare B" event. This event is sent to the action-qualifier where it is qualified and converted it into one or
more actions. These actions can be applied to either the EPWMxA or the EPWMxB output depending on
the configuration of the AQCTLA and AQCTLB registers. The actions that can be defined in the AQCTLA
and AQCTLB registers include:
• Do nothing. event is ignored.
• Clear: Pull the EPWMxA and/or EPWMxB signal low.
• Set: Pull the EPWMxA and/or EPWMxB signal high.
• Toggle the EPWMxA and/or EPWMxB signal.
Shadowing of this register is enabled and disabled by the CMPCTL[SHDWBMODE] bit. By default this
register is shadowed.
• If CMPCTL[SHDWBMODE] = 0, then the shadow is enabled and any write or read will automatically go
to the shadow register. In this case, the CMPCTL[LOADBMODE] bit field determines which event will
load the active register from the shadow register:
• Before a write, the CMPCTL[SHDWBFULL] bit can be read to determine if the shadow register is
currently full.
• If CMPCTL[SHDWBMODE] = 1, then the shadow register is disabled and any write or read will go
directly to the active register, that is the register actively controlling the hardware.
• In either mode, the active and shadow registers share the same memory map address.