R01UH0823EJ0100 Rev.1.00
Page 823 of 1823
Jul 31, 2019
RX23W Group
30. Watchdog Timer (WDTA)
CKS[3:0] Bits (Clock Division Ratio Selection)
These bits specify the division ration of the clock used for the down-counter. The division ration can be selected from
among the peripheral module clock (PCLK) divided by 4, 64, 128, 512, 2048, and 8192. Combined with the TOPS[1:0]
bit setting, a count period between 4,096 and 134,217,728 cycles of the PCLK clock can be selected for the WDT.
RPES[1:0] Bits (Window End Position Selection)
These bits specify the window end position that indicates the refresh-permitted period. 75%, 50%, 25%, or 0% of the
timeout period can be selected for the window end position. The selected window end position should be a value smaller
than the window start position (window start position > window end position). If the window end position is greater than
the window start position, only the window start position setting is enabled.
RPSS[1:0] Bits (Window Start Position Selection)
These bits specify the window start position that indicates the refresh-permitted period. 25%, 50%, 75%, or 100% of the
timeout period can be selected for the window end position. The window start position should be set to a value greater
the window end position. If the window start position is set to a value smaller than or equal to the window end position,
the window end position is set to 0%.
Table 30.2
Timeout Period Settings
CKS[3:0] Bits
Clock Division Ratio
Timeout Period
(Number of Cycles)
Cycles of PCLK Clock
b7
b6
b5
b4
b1
b0
0
0
0
1
0
0
Divide-by-4
1024
4096
0
1
4096
16384
1
0
8192
32768
1
1
16384
65536
0
1
0
0
0
0
Divide-by-64
1024
65536
0
1
4096
262144
1
0
8192
524288
1
1
16384
1048576
1
1
1
1
0
0
Divide-by-128
1024
131072
0
1
4096
524288
1
0
8192
1048576
1
1
16384
2097152
0
1
1
0
0
0
Divide-by-512
1024
524288
0
1
4096
2097152
1
0
8192
4194304
1
1
16384
8388608
0
1
1
1
0
0
Divide-by-2048
1024
2097152
0
1
4096
8388608
1
0
8192
16777216
1
1
16384
33554432
1
0
0
0
0
0
Divide-by-8192
1024
8388608
0
1
4096
33554432
1
0
8192
67108864
1
1
16384
134217728