r5f21346mnfp Renesas Electronics Corporation., r5f21346mnfp Datasheet - Page 218

• Manufacturer Part Number: r5f21346mnfp
• Description: Single-chip Mcus Incorporates The R8c Cpu Core
• Manufacturer: Renesas Electronics Corporation.

R8C/34M Group
R01UH0131EJ0100 Rev.1.00
Jun 21, 2011
14.3
Figure 14.2
14.3.1
Count starts
14.3.1.1
0%
Note:
1. A watchdog timer interrupt or watchdog timer reset is generated.
The period for acknowledging refreshment operation to the watchdog timer (write to the WDTR register) can
be selected by bits WDTRCS0 and WDTRCS1 in the OFS2 register. Figure 14.2 shows the Refresh
Acknowledgement Period for Watchdog Timer.
Assuming that the period from when the watchdog timer starts counting until it underflows is 100%, a refresh
operation executed during the refresh acknowledgement period is acknowledged. Any refresh operation
executed during the period other than the above is processed as an incorrect write, and a watchdog timer
interrupt or watchdog timer reset (selectable by the PM12 bit in the PM1 register) is generated.
Do not execute any refresh operation while the count operation of the watchdog timer is stopped.
Processed as
incorrect write
Processed as incorrect write
Functional Description
Common Items for Multiple Modes
Processed as incorrect write
Refresh Acknowledgement Period
Refresh Acknowledgement Period for Watchdog Timer
25%
(1)
Refresh can be acknowledged
Watchdog timer period
Refresh can be acknowledged
(1)
50%
Refresh can be acknowledged
(1)
75%
Refresh can be
acknowledged
Underflow
100%
Refresh acknowledge period
100% (WDTRCS1 to WDTRCS0 = 11b)
75% (WDTRCS1 to WDTRCS0 = 10b)
50% (WDTRCS1 to WDTRCS0 = 01b)
25% (WDTRCS1 to WDTRCS0 = 00b)
WDTRCS0, WDTRCS1: Bits in OFS2 register
14. Watchdog Timer
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