h8s-2158 Renesas Electronics Corporation., h8s-2158 Datasheet - Page 437

• Manufacturer Part Number: h8s-2158
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

15.6.5
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 15.8.
15.6.6
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 pulse generator 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.
Counter Values during Transitions between High-Speed, Sub-Active, and Watch
System Reset by RESO
Modes
Figure 15.8 Sample Circuit for Resetting the System by the RESO
Reset signal for entire system
RESO Signal
RESO
RESO
Reset input
Rev. 3.00 Jan 25, 2006 page 385 of 872
Section 15 Watchdog Timer (WDT)
RESO
RES
This LSI
RESO Signal
RESO
RESO
REJ09B0286-0300