M16C6K9 Datasheet, PDF (177/292 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6K9 Group
Serial Interrupt Output
(3) Clock restart/ stop inhibition request
_______________
Asserting the CLKRUN signal can request to restart or maintain the clock which stops or slows
down or request the host to tend to stop or slow down.
Fig.SI-11 shows an example of timing of clock restart request, Fig.SI-12 shows an example of
timing of clock stop inhibition request.
➀Clock restart operation
Setting the clock restart bit of serial interrupt control register0 to “1” will request the clock restart if
the clock has slowed down or stopped at serial interrupt request.
LCLK
CLKRUN line
System•CLKRUN
Device•CLKRUN
SERIRQ line
System•SERIRQ
Device•SERIRQ
f1
Serial interrupt request
Internal Interrupt restart
request signal
Restart frame
Start frame
Fig.SI-11 Timing diagram of clock restart request
➁Clock stop inhibition request
Setting the clock stop inhibition bit of serial interrupt control register0 to “1” will request the inhibi-
tion of clock stop if the clock tends to stop or slow down during all the period of serial interrupt
output.
Clock
CLKRUN line
System•CLKRUN
Device•CLKRUN
SERIRQ line
Serial interrupt request
Internal Interrupt Inhibition
request signal
Inhibition
request
A cycle of serial interrupt
Fig.SI-12 Example of timing of clock stop inhibition request
Rev.1.00 Jun 06, 2003 page 177 of 290