h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 436

• 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)
14.3.2
To use the WDT as an interval timer, clear the WT/IT bit in TCSR to 0 and set the TME bit to 1.
An interval timer interrupt (WOVI) is generated each time TCNT overflows, provided that the
WDT is operating as an interval timer, as shown in figure 14.4. This function can be used to
generate interrupt requests at regular intervals.
Rev. 4.00 Jun 06, 2006 page 382 of 1004
REJ09B0301-0400
Legend:
WT/IT: Timer mode select bit
TME:
OVF:
Note: * Cleared to 0 by an internal reset when OVF is set to 1. XRST is cleared to 0.
Internal reset signal
Interval Timer Operation
Timer enable bit
Overflow flag
H'FF
H'00
TCNT value
WT/IT = 1
TME = 1
Figure 14.3 Operation in Watchdog Timer Mode
H'00 written
to TCNT
518 system clock periods
Overflow
OVF = 1 *
WT/IT = 1
TME = 1
H'00 written
to TCNT
Time