Fujitsu FR81S User Manual
CHAPTER 19: BASE TIMER
2. Features
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER
: BASE TIMER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
5
2.1. 16/32-bit Reload Timer
This section explains the 16/32-bit reload timer of the base timer.
A base timer can be used as a 16/32-bit reload timer. The 16/32-bit reload timer is a timer that decreases from
a preset value.
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.
Timer mode
You can run multiple timers for individual channels and can combine 16-bit reload timers for two channels
into one 32-bit reload timer.
Operation mode
You can select one of the following two:
⋅
Reload mode: In this mode, when the down counter underflows, the preset value (cycle) is reloaded to
allow the timer to restart counting.
⋅
One-shot mode: Once the down counter underflows, the counter will no longer count.
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
⋅
External event: Rising edge, falling edge, or both edges
⋅
16/32-bit reload timer reactivation: The 16/32-bit reload 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
⋅
IRQ1: When a 16/32-bit reload timer activation trigger is detected
MB91520 Series
MN705-00010-1v0-E
638