MB95630H Series
MN702-00009-1v0-E
FUJITSU SEMICONDUCTOR LIMITED
173
CHAPTER 11 8/16-BIT COMPOSITE TIMER
11.15 Notes on Using 8/16-bit Composite
Timer
11.15
Notes on Using 8/16-bit Composite Timer
This section provides notes on using the 8/16-bit composite timer.
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Notes on Using 8/16-bit Composite Timer
•
To switch the timer function with the timer operating mode select bits (Tn0CR0/
Tn1CR0:F[3:0]), stop the timer operation first (Tn0CR1/Tn1CR1:STA = 0), then clear the
interrupt flag (Tn0CR1/Tn1CR1:IF, IR), the interrupt enable bits (Tn0CR1/Tn1CR1:IE,
Tn0CR0/Tn1CR0:IFE) and the buffer full flag (Tn0CR1/Tn1CR1:BF).
•
In the case of using the input capture function, when both edges of the external input signal
is selected as the timing at which the 8/16-bit composite timer captures a counter value
(Tn0CR0/Tn1CR0:F[3:0] = 0b1100 or 0b1111) while "H" level external input signal is
being input, the first falling edge will be ignored, no counter value will be transferred to the
data register (Tn0DR/Tn1DR), and pulse width measurement completion/edge detection
flag (Tn0CR1/Tn1CR1:IR) will not be set either.
- In counter clear mode, the counter will not be cleared at the first falling edge and no data
will be transferred to the data register either. The 8/16-bit composite timer will start the
input capture operation from the next rising edge.
- In counter free-run mode, no data will be transferred to the data register at the first falling
edge. The 8/16-bit composite timer will start the input capture operation from the next
rising edge.
•
In 8-bit operating mode (TMCRn:MOD = 0) of the PWM timer function (variable-cycle
mode), when modifying the 8/16-bit composite timer data registers (Tn0DR and Tn1DR)
during counter operation, modify Tn1DR first and then Tn0DR.
•
The counter stops operating while holding the value when the microcontroller transits to
stop mode or watch mode. When the stop mode or watch mode is released by an interrupt,
the counter resumes operating with the last value that it holds (see Figure 11.15-1 and
Figure 11.15-2). Therefore, the first interval time or the initial external clock count value is
incorrect. Always initialize the counter value after the microcontroller is released from stop
mode or watch mode.