Fujitsu FR81S User Manual
CHAPTER 19: BASE TIMER
2. Features
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER
: BASE TIMER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
7
2.3. 16/32-bit PWC Timer
This section explains the overview of the 16/32-bit PWC timer of the base timer.
The 16/32-bit PWC timer, PWC standing for Pulse Width Counter, is used to measure pulse widths or cycles.
I/O mode
You can select a signal (waveform) I/O operation using the base timer I/O selection function.
Timer mode
You can run multiple timers for individual channels and can combine 16-bit PWC timers for two channels into
one 32-bit PWC timer.
Operation mode
You can select one of the following two:
⋅
Single measurement mode: In this mode, measurement is conducted only once.
⋅
Continuous measurement mode: In this mode, after one sequence of measurement is conducted, the
input of the next measurement start edge is awaited and the detection
of the next measurement start edge triggers another sequence of
measurement.
Count clock
You can select one of the internal (peripheral) clocks obtained by dividing the frequency of the peripheral
clock (PCLK) by five types.
⋅
Clocks obtained by dividing the frequency of the peripheral clock (PCLK) by 1, 4, 16, 128, and 256.
Measurement mode
You can select one of the following five options relating to the pulse width and cycle to be measured:
⋅
"H" pulse width: Duration in which the input signal is maintained at the "H" level
⋅
"L" pulse width: Duration in which the input signal is maintained at the "L" level
⋅
Rising edge interval: Period from the detection of a rising edge to the detection of the next rising edge
⋅
Falling edge interval: Period from the detection of a falling edge to the detection of the next falling edge
⋅
Edge-to-edge pulse width: The width between consecutive input edges is one of the following:
⋅
Period from the detection of a rising edge to the detection of the falling edge
⋅
Period from the detection of a falling edge to the detection of the rising edge
16/32-bit PWC timer reactivation
The 16/32-bit PWC timer can be reactivated when an activation trigger is detected during counting.
Interrupt request
An interrupt request can be generated in one of the following events:
⋅
IRQ0 : When an overflow occurs
⋅
IRQ1 : When measurement ends
MB91520 Series
MN705-00010-1v0-E
640