Enhanced PWM (ePWM) Module
www.ti.com
15.2.4.2.2 Counter-Compare A Register (CMPA)
The counter-compare A register (CMPA) is shown in Figure 15-76 and described in Table 15-67.
Figure 15-76. Counter-Compare A Register (CMPA)
15 0
CMPA
R/W-0
LEGEND: R/W = Read/Write; -n = value after reset
Table 15-67. Counter-Compare A Register (CMPA) Field Descriptions
Bits Name Value Description
15-0 CMPA 0-FFFFh The value in the active CMPA register is continuously compared to the time-base counter (TBCNT).
When the values are equal, the counter-compare module generates a "time-base counter equal to
counter compare A" 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; the 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[SHDWAMODE] bit. By default this
register is shadowed.
• If CMPCTL[SHDWAMODE] = 0, then the shadow is enabled and any write or read will automatically
go to the shadow register. In this case, the CMPCTL[LOADAMODE] bit field determines which event
will load the active register from the shadow register.
• Before a write, the CMPCTL[SHDWAFULL] bit can be read to determine if the shadow register is
currently full.
• If CMPCTL[SHDWAMODE] = 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.
1588
Pulse-Width Modulation Subsystem (PWMSS) SPRUH73H–October 2011–Revised April 2013
Submit Documentation Feedback
Copyright © 2011–2013, Texas Instruments Incorporated
To Next Page
Loading...
Need help?
General
