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Timer Start/Stop Synchronization
and the current 16-bit timer values. The new Timer 2 and overflow count values are loaded into the timer,
and the timer enters the RUN mode.
T2CTRL.STATE
= 1 indicates that the module is running. This
synchronous start process takes 86 clock cycles from the time when the 32-kHz clock rising edge is
sampled high. The synchronous start-and-stop function requires that the system clock frequency is
selected to be 32 MHz. If the 16-MHz clock is selected, an offset is added to the new calculated value.
If a synchronous start is done without a previous synchronuous stop, the timer is loaded with
unpredictable values. To avoid this, do the first start of the timer asynchronously, then enable
synchronous mode for subsequent stops and starts.
The method for calculating the new Timer 2 value and overflow-count value is given as follows. Because
the Timer 2 and Sleep Timer clocks are asynchronous with a noninteger clock ratio, there is an error of
maximum
±
1 in the calculated timer value compared to the ideal timer value, not taking clock inaccuracies
into account.
211
SWRU191C
–
April 2009
–
Revised January 2012
Timer 2 (MAC Timer)
Copyright
©
2009
–
2012, Texas Instruments Incorporated