Texas Instruments MSP430x1xx - Manual (Page 190)

Timer Modes
11-14
those in the up mode. See Section 11.3.2.1 for details. However, if the timer
is counting in the down direction when TBCL0 is updated, it continues its
descent until it reaches zero. The new period takes effect only after the counter
finishes counting down to zero. See Figure 11–16.
Note:
If TBCL0 > TBR
(max),
the counter operates as if it were configured for
continuous mode. It will not count down from TBR
(max)
to zero.
Figure 11–16.Altering TBCL0—Timer in Up/Down Mode
0 1 2 3 4 5 4 3 2 1 0 1 2 3 4 3 2 1 0 1 2 3 2 1 0 1 2 1 0 1 2 3 4 5 4 3 2 1 0 1 2 1
5 4 2 5 2
5
4
3
2
1
0
Timer
Register
2 TBCL0