H8S2110B RENESAS [Renesas Technology Corp], H8S2110B Datasheet - Page 258

• Manufacturer Part Number: H8S2110B
• Description: Renesas 16-Bit Single-Chip Microcomputer Renesas H8S Family/H8S/2100 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 11 Watchdog Timer (WDT)
11.6.5
Inputting the RESO output signal to the RESO pin of this LSI prevents the LSI from being
initialized correctly; the RESO signal must not be logically connected to the RES pin of the LSI.
To reset the entire system by the RESO signal, use the circuit as shown in figure 11.8.
11.6.6
When WDT_1 is used as a clock counter and is allowed to transit between high-speed mode and
sub-active or watch mode, the counter does not display the correct value due to internal clock
switching.
Specifically, when transiting from high-speed mode to sub-active or watch mode, that is, when the
control clock for WDT_1 switches from the main clock to the sub-clock, the counter incrementing
timing is delayed for approximately two to three clock cycles.
Similarly, when transiting from sub-active or watch mode to high-speed mode, the clock is not
supplied until stabilized internal oscillation is available because the main clock oscillator is halted
in sub-clock mode. The counter is therefore prevented from incrementing for the time specified by
the STS2 to STS0 bits in SBYCR after internal oscillation starts, thus producing counter value
differences for this time.
Special care must be taken when using WDT_1 as a clock counter. Note that no counter value
difference is produced while operated in the same mode.
Rev. 2.00 Mar 21, 2006 page 220 of 518
REJ09B0299-0200
System Reset by RESO
Counter Values during Transitions between High-Speed, Sub-Active, and Watch
Modes
Figure 11.8 Sample Circuit for Resetting System by RESO
Reset signal for entire system
RESO Signal
RESO
RESO
Reset input
RESO Signal
RESO
RESO
RESO
RES
This LSI