Fujitsu F2MC-8L MB89620 Series Hardware Manual page 180

Note: The following shows an example of the interval time and square wave output frequency.
For an 8 MHz source oscillation (F
and a count clock cycle of one instruction cycle, the interval time and square wave output frequency
are calculated as follows:
n Pulse Width Measurement Function
The pulse width measurement function can measure the "H" width, "L" width, and one-cycle
width of pulses input to an external pin (PWC pin).
• The PWC can perform continuous pulse width measurement.
• The measurement speed (internal count clock) can be selected from three different speeds.
• The width of long input pulses can be measured using an interrupt processing routine.
Table 8.1b lists the available pulse widths measured by the pulse width measurement function.
Table 8.1b Available Pulse Width Measured by Pulse Width
Internal count clock cycle
t : Instruction cycle (divide-by-four source oscillation)
inst
MB89620 series
= (1 × 4/F
Interval time
= (4/10 MHz) × (221 + 1)
88.8 µ s
=
/(1 × 8 × (RLBR register value + 1))
Output frequency = F
C
= 10 MHz/ (8 × (221 + 1))
5.6 kHz
=
RLBR register value of "00
H
Measurement Function
1 t
inst
4 t
inst
32 t
inst
), a PWC reload buffer register (RLBR) value of "DD
C
) × (RLBR register value + 1)
C
" is assumed as 256.
Interval time
1 t to 2 8 t
inst inst
2 2 t to 2 10 t
inst inst
t
2 5 to 2 13 t
inst inst
CHAPTER 8 PULSE WIDTH COUNT TIMER (PWC)
(221)",
H
159