Fujitsu F2MC-16LX Hardware Manual page 394

CHAPTER 15 PWC TIMER
Table 15.3-6 The Measurement Mode List (2/2)
Measurement MOD2 MOD1 MOD0
mode
Measurement at
cycle of dividing 0
frequency
No timer count is performed from start of the count to input of the count start edge in any modes. The timer
is cleared to 0000
clock until the count termination edge is input. When the count termination edge is input, the next operation
is executed.
1. Measurement ending flag (EDIR) in PWCSR is set.
2. The timer count operation stops (excluding when it is at the same time of restarting).
3. Continuous measurement mode: The timer value (measured result) is transferred to the PWCR and the
4. Single measurement mode: The measurement is terminated (excluding when it is at the same time of
When the pulse width measurement between all edges or the division measurement is performed in the
continuous measurement mode, the termination edge is the next measurement edge.
Minimum Input Pulse Width
There are following limitations for pulses that can be input to width measurement input terminals (PWC).
Pulse width must be 4-machine cycle (0.17 µs for the 24-MHz machine clock) or more.
Calculation Method of Pulse Width/cycle
Pulse width/cycle to be measured can be calculated by the following expression:
=n • t/D
T
W
T : pulse width to be measured/cycle (µs)
W
n: Measurement result data in PWCR
t: Count Clock cycle (µs)
D : Division ratio selected by the division ratio register DIVR
IV
(Frequency of dividing frequency measurement mode)
378
1 1
For only dividing ratio selected by division setting register DIVR
The input pulse is divided and the cycle is measured.
Count (measurement) start: when detecting a rising edge immediately after
counting starts
Count (measurement) end: when one cycle ends after it is divided
after inputting the count start edge and the timer count is performed at every count
H
count is suspended until the next measurement start edge is input.
restarting).
(µs)
IV
Measurement mode measured target
(W: width of a measured pulse)
W W
Count stop
Count start
Start
(Example of 4 division)
W
Stop