4.3 Action-Qualifier Submodule Registers
Action-Qualifier Submodule Registers
Figure 4-8. 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 4-8. Counter-Compare Control Register (CMPCTL) Field Descriptions
Bits Name Value Description
15-10 Reserved 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 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 Active Counter-Compare B (CMPB) Load From Shadow Select Mode
This bit has no effect in immediate mode (CMPCTL[SHDWBMODE] = 1).
00 Load on CTR = Zero: Time-base counter equal to zero (TBCTR = 0x0000)
01 Load on CTR = PRD: Time-base counter equal to period (TBCTR = TBPRD)
10 Load on either CTR = Zero or CTR = PRD
11 Freeze (no loads possible)
1-0 LOADAMODE Active Counter-Compare A (CMPA) Load From Shadow Select Mode.
This bit has no effect in immediate mode (CMPCTL[SHDWAMODE] = 1).
00 Load on CTR = Zero: Time-base counter equal to zero (TBCTR = 0x0000)
01 Load on CTR = PRD: Time-base counter equal to period (TBCTR = TBPRD)
10 Load on either CTR = Zero or CTR = PRD
11 Freeze (no loads possible)
Figure 4-9 through Figure 4-12 and Table 4-9 through Table 4-12 provide the action-qualifier submodule
register definitions.
SPRU791D – November 2004 – Revised October 2007 Registers 99
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