Texas Instruments MSP430x1xx - Manual (Page 156)

Timer Modes
10-16
Figure 10–20. Capture Cycle
Second
Capture
Taken
COV = 1
Capture
Taken
No
Capture
Taken
Read
Taken
Capture
Clear Bit COV
in Register CCTL
Idle
Idle
Capture
Capture Read and No Capture
Capture
Capture Read Capture
Overflow bit COVx is reset by the software as described in the following
example:
; Software example for the handling of captured data
; looking for overflow condition
;
; The data of the capture/compare register CCRx are taken
; by the software and immediately with the next
; instruction the overflow bit is tested and a decision is
; made to proceed regularly or with an error handler
;
CCRx_Int_hand
... ; Start of handler Interrupt
...
...
MOV &CCRx,RAM_Buffer
BIT #COV,&CCTLx
JNZ Overflow_Hand
...
...
...
RETI
Overflow_Hand BIC #COV,&CCTLx ; reset capture
; overflow flag
; get back to lost
; synchronization
...
...
; RETI
Note: Capture With Timer Halted
The capture should be disabled when the timer is halted. The sequence to
follow is: stop the capture, then stop the timer. When the capture function is
restarted, the sequence should be: start the capture, then start the timer.