Fujitsu FR81S User Manual
CHAPTER 19: BASE TIMER
2. Features
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER
: BASE TIMER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
8
2.4. 16-bit PPG Timer
This section explains the 16-bit PPG timer of the base timer.
The 16-bit PPG timer, PPG standing for Programmable Pulse Generator Timer, is a timer that generates a
waveform with a desired pulse width.
I/O mode
You can select a signal (external clock, external activation trigger, waveform) I/O operation using the base
timer I/O selection function.
Operation mode
You can select one of the following two:
⋅
Reload mode: A sequence of "L"-level and "H"-level signals (consecutive pulses) is output.
⋅
One-shot mode: A string of one "L"-level signal and one "H"-level signal (single pulses) is output.
Count clock
You can select one of five internal (peripheral) clocks and three external clocks (ECK signals).
⋅
Internal clock (peripheral clock): Clock obtained by dividing the frequency of the peripheral clock
(PCLK) by 1, 4, 16, 128, or 256.
⋅
External clock (ECK signal): Rising edges, falling edges, or both edges are detected.
Activation trigger
One of the following can be selected:
⋅
Software trigger
⋅
Three external events: (Rising edge, falling edge, or both edges detection)
16-bit PPG timer reactivation
The 16-bit PPG 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 underflow occurs based on the value of the base timer x H width setting reload register
(BTxPRLH).
⋅
IRQ1 : When a 16-bit PPG timer activation trigger is detected.
MB91520 Series
MN705-00010-1v0-E
641