h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 432

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 14 Watchdog Timer (WDT)
TCSR1 Bit 4—Prescaler Select (PSS): Selects the input clock source for TCNT in WDT1. For
details, see the description of the CKS2 to CKS0 bits below.
TCSR1
Bit 4
PSS
0
1
Bit 3—Reset or NMI (RST/NMI
requested on TCNT overflow in watchdog timer mode.
Bit 3
RST/NMI
0
1
Bits 2 to 0—Clock Select 2 to 0 (CKS2 to CKS0): These bits select an internal clock source,
obtained by dividing the system clock ( ), or subclock ( SUB) for input to TCNT.
Bit 2
CKS2
0
1
Note:
Rev. 4.00 Jun 06, 2006 page 378 of 1004
REJ09B0301-0400
WDT0 input clock selection
NMI
NMI
NMI
* The overflow period is the time from when TCNT starts counting up from H'00 until
Bit 1
CKS1
0
1
0
1
overflow occurs.
Description
TCNT counts -based prescaler (PSM) divided clock pulses
TCNT counts SUB-based prescaler (PSS) divided clock pulses
Description
An NMI interrupt is requested
An internal reset is requested
Bit 0
CKS0
0
1
0
1
0
1
0
1
NMI
NMI
NMI): Specifies whether an internal reset or NMI interrupt is
Clock
/2 (Initial value)
/64
/128
/512
/2048
/8192
/32768
/131072
Overflow Period * (when
25.6 µs
819.2 µs
1.6 ms
6.6 ms
26.2 ms
104.9 ms
419.4 ms
1.68 s
Description
= 20 MHz)
(Initial value)
(Initial value)