Fujitsu FR81S User Manual
CHAPTER 21: 32-BIT FREE-RUN TIMER
7. Q&A
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER
: 32-BIT FREE-RUN TIMER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
36
7.2. How to Select the External Clock?
This section shows how to select the external clock.
You can configure it using the clock selection bits (TCCSn.ECKE [n=3 to 5]), data direction bits and port
function bits.
To set to external
clock input
Configuration
Pin
Pulse width
(H width,
L width)
Free-run timer 3
Set the clock
selection bit
(ECKE) to "1".
Set the FRCK3 pin for peripheral input.
(See "CHAPTER: I/O PORTS".)
FRCK3
4/F
PCLK
or higher
Free-run timer 4
Set the FRCK4 pin for peripheral input.
(See "CHAPTER: I/O PORTS".)
FRCK4
Free-run timer 5
Set the FRCK2 pin for peripheral input.
(See "CHAPTER: I/O PORTS".)
FRCK2
MB91520 Series
MN705-00010-1v0-E
831