h8s-2110b Renesas Electronics Corporation., h8s-2110b Datasheet - Page 477

• Manufacturer Part Number: h8s-2110b
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

SLEEP instruction is executed (power-down mode transition), the subclock input circuit is
not initialized and an error may occur in the microcomputer.
Before power-down mode is entered with using the subclock, at least two cycle of the 32-kHz
clock should be input after the 32-kHz clock input is enabled (EXCLE = 1).
As described in the hardware manual (clock pulse generator/subclock input circuit), when the
subclock is not used, the subclock input should not be enabled (EXCLE = 0).
18.6
To remove noise from the subclock input at the EXCL pin, the subclock is sampled by a divided
clock. The sampling frequency is set by the NESEL bit in LPWRCR.
The subclock is not sampled in subactive mode, subsleep mode, or watch mode.
18.7
The clock select circuit selects the system clock that is used in this LSI.
A clock generated by an oscillator to which the EXTAL and XTAL pins are input is selected as a
system clock when returning from high-speed mode, medium-speed mode, sleep mode, reset state,
or standby mode.
A subclock input from the EXCL pin is selected as a system clock in subactive mode, subsleep
mode, or watch mode. At this time, modules such as the CPU, TMR_0, TMR_1, WDT_0,
WDT_1, ports, and interrupt controller and their functions operate depending on the SUB. The
count clock and sampling clock for each timer are divided SUB clocks.
18.8
18.8.1
Since all kinds of characteristics of the resonator are closely related to the board design by the
user, use the example of resonator connection in this document for only reference; be sure to use
an resonator that has been sufficiently evaluated by the user. Consult with the resonator
manufacturer about the resonator circuit ratings which vary depending on the stray capacitances of
the resonator and installation circuit. Make sure the voltage applied to the oscillator pins does not
exceed the maximum rating.
Waveform Forming Circuit
Clock Select Circuit
Usage Notes
Note on Resonator
Rev. 2.00 Mar 21, 2006 page 439 of 518
Section 18 Clock Pulse Generator
REJ09B0299-0200