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16.7
Usage Notes on the PWC Timer
Notes on using the PWC timer are given below.
■ Usage Notes on the PWC Timer
●
Notes about using a program for setting
• Changing the following PWCS0/PWCS1 bit values is prohibited during timer operation. The bit values
are changed only before the timer is started or after the operation is discontinued.
[bit7, bit6] CKS1 and CKS0: Clock selection bits
[bit3] S/C: Measurement mode (single or continuous) selection bit
[bit2 to bit0] MOD2, MOD1, and MOD0: Operation mode and measurement edge selection bits
Note that the value of pulse output level indication bit (POUT: bit8) remains unchanged even if the bit
is written during timer operation.
• Changing the DIV0/DIV1 value is prohibited during timer operation. Change the DIV0/DIV1 value
before the timer is started or after the operation has stopped.
• Setting the clock selection bits CKS1 and CKS0 of PWC control status register (PWCSL0/PWCSL1) to
11
is prohibited.
B
• The PWC0/PWC1 and timer values are determined when the timer is set in the one-shot mode or after
the operation is terminated in reload timer mode. Therefore, always set the values after the timer is
used.
• The PWC0/PWC1 value is undefined if the timer is set in reload timer mode after the operation is
discontinued in the one-shot mode. Therefore, always set the value before the timer is used.
• To change the mode from pulse-width measurement mode to timer mode, always set the value in
PWC0/PWC1 before the timer has started.
• When division period measurement mode is used in pulse-width measurement mode, the input pulse is
divided. Note that the pulse width calculated from the count result becomes a mean.
• During continuous measurement in pulse-width measurement mode, the division circuit for an internal
count clock is not cleared, and the number of edges smaller than the count clock is added to the count
result.
CHAPTER 16 PWC Timer
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