Texas Instruments MSP430x4xx - Manual (Page 214)

Timer_A Operation
12-5 Timer_A
12.2.2 Starting the Timer
The timer may be started, or restarted in the following ways:
- The timer counts when MCx > 0 and the clock source is active.
- When the timer mode is either up or up/down, the timer may be stopped
by writing 0 to TACCR0. The timer may then be restarted by writing a
nonzero value to TACCR0. In this scenario, the timer starts incrementing
in the up direction from zero.
12.2.3 Timer Mode Control
The timer has four modes of operation as described in Table 12−1: stop, up,
continuous, and up/down. The operating mode is selected with the MCx bits.
Table 12−1.Timer Modes
MCx Mode Description
00 Stop The timer is halted.
01 Up The timer repeatedly counts from zero to the value of
TACCR0
10 Continuous The timer repeatedly counts from zero to 0FFFFh.
11 Up/down The timer repeatedly counts from zero up to the value of
TACCR0 and back down to zero.