Enhanced PWM (ePWM) Module
15.2.4.2.1 Counter-Compare Control Register (CMPCTL)
The counter-compare control register (CMPCTL) is shown in
and described in
Figure 15-75. Counter-Compare Control Register (CMPCTL)
15
10
9
8
Reserved
SHDWBFULL
SHDWAFULL
R-0
R-0
R-0
7
6
5
4
3
2
1
0
Reserved
SHDWBMODE
Reserved
SHDWAMODE
LOADBMODE
LOADAMODE
R-0
R/W-0
R-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 15-66. Counter-Compare Control Register (CMPCTL) Field Descriptions
Bits
Name
Value Description
15-10
Reserved
0
Reserved
9
SHDWBFULL
Counter-compare B (CMPB) Shadow Register Full Status Flag. This bit self clears once a load-strobe
occurs.
0
CMPB shadow FIFO not full yet
1
Indicates the CMPB shadow FIFO is full; a CPU write will overwrite current shadow value.
8
SHDWAFULL
Counter-compare A (CMPA) Shadow Register Full Status Flag. The flag bit is set when a 32-bit write to
CMPA:CMPAHR register or a 16-bit write to CMPA register is made. A 16-bit write to CMPAHR register
will not affect the flag. This bit self clears once a load-strobe occurs.
0
CMPA shadow FIFO not full yet
1
Indicates the CMPA shadow FIFO is full, a CPU write will overwrite the current shadow value.
7
Reserved
0
Reserved
6
SHDWBMODE
Counter-compare B (CMPB) Register Operating Mode
0
Shadow mode. Operates as a double buffer. All writes via the CPU access the shadow register.
1
Immediate mode. Only the active compare B register is used. All writes and reads directly access the
active register for immediate compare action.
5
Reserved
Reserved
4
SHDWAMODE
Counter-compare A (CMPA) Register Operating Mode
0
Shadow mode. Operates as a double buffer. All writes via the CPU access the shadow register.
1
Immediate mode. Only the active compare register is used. All writes and reads directly access the
active register for immediate compare action
3-2
LOADBMODE
0-3h
Active Counter-Compare B (CMPB) Load From Shadow Select Mode. This bit has no effect in
immediate mode (CMPCTL[SHDWBMODE] = 1).
0
Load on CTR = 0: Time-base counter equal to zero (TBCNT = 0000h)
1h
Load on CTR = PRD: Time-base counter equal to period (TBCNT = TBPRD)
2h
Load on either CTR = 0 or CTR = PRD
3h
Freeze (no loads possible)
1-0
LOADAMODE
0-3h
Active Counter-Compare A (CMPA) Load From Shadow Select Mode. This bit has no effect in
immediate mode (CMPCTL[SHDWAMODE] = 1).
0
Load on CTR = 0: Time-base counter equal to zero (TBCNT = 0000h)
1h
Load on CTR = PRD: Time-base counter equal to period (TBCNT = TBPRD)
2h
Load on either CTR = 0 or CTR = PRD
3h
Freeze (no loads possible)
1587
SPRUH73H – October 2011 – Revised April 2013
Pulse-Width Modulation Subsystem (PWMSS)
Copyright © 2011–2013, Texas Instruments Incorporated