R01UH0822EJ0100 Rev.1.00
Page 581 of 1041
Jul 31, 2019
RX13T Group
22. Independent Watchdog Timer (IWDTa)
22.3.8
Correspondence between Option Function Select Register 0 (OFS0) and IWDT
Registers
lists the correspondence between option function select register 0 (OFS0) used in auto-start mode and the
registers used in register start mode.
Do not change the OFS0 register setting during IWDT operation.
For details on the OFS0 register, refer to
section 7.2.1, Option Function Select Register 0 (OFS0)
22.4
Usage Notes
22.4.1
Refresh Operations
When making the settings to control the timing of refreshing, consider variations in the range of errors due to the
accuracy of the PCLK and IWDTCLK and set values which ensure that refreshing is possible.
22.4.2
Clock Divide Ratio Setting
Satisfy the frequency of the peripheral module clock (PCLK) ≥ 4 × (the frequency of the count source after divide).
Table 22.5
Correspondence between Option Function Select Register 0 (OFS0) and IWDT Registers
Target of Control
Function
OFS0 Register
(Enabled in Auto-Start Mode)
OFS0.IWDTSTRT = 0
IWDT Registers
(Enabled in Register Start Mode)
OFS0.IWDTSTRT = 1
Counter
Timeout period selection
OFS0.IWDTTOPS[1:0]
IWDTCR.TOPS[1:0]
Clock frequency divide ratio selection OFS0.IWDTCKS[3:0]
IWDTCR.CKS[3:0]
Window start position selection
OFS0.IWDTRPSS[1:0]
IWDTCR.RPSS[1:0]
Window end position selection
OFS0.IWDTRPES[1:0]
IWDTCR.RPES[1:0]
Reset output or
interrupt request
output
Reset output or interrupt request
output selection
OFS0.IWDTRSTIRQS
IWDTRCR.RSTIRQS
Count stop
Sleep mode count stop control
OFS0.IWDTSLCSTP
IWDTCSTPR.SLCSTP