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HD6433694 Datasheet, PDF (99/432 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Tiny Series
5.2.2 Pin Connection when Not Using Subclock
When the subclock is not used, connect pin X1 to VCL or VSS and leave pin X2 open, as shown in
figure 5.10.
VCL or VSS
X1
X2
Open
Figure 5.10 Pin Connection when not Using Subclock
5.3 Prescalers
5.3.1 Prescaler S
Prescaler S is a 13-bit counter using the system clock (φ) as its input clock. It is incremented once
per clock period. Prescaler S is initialized to H'0000 by a reset, and starts counting on exit from
the reset state. In standby mode, subactive mode, and subsleep mode, the system clock pulse
generator stops. Prescaler S also stops and is initialized to H'0000. The CPU cannot read or write
prescaler S. The output from prescaler S is shared by the on-chip peripheral modules. The divider
ratio can be set separately for each on-chip peripheral function. In active mode and sleep mode,
the clock input to prescaler S is determined by the division factor designated by MA2 to MA0 in
SYSCR2.
5.3.2 Prescaler W
Prescaler W is a 5-bit counter using a 32.768 kHz signal divided by 4 (φW/4) as its input clock. The
divided output is used for clock time base operation of timer A. Prescaler W is initialized to H'00
by a reset, and starts counting on exit from the reset state. Even in standby mode, subactive mode,
or subsleep mode, prescaler W continues functioning so long as clock signals are supplied to pins
X1 and X2. Prescaler W can be reset by setting 1s in bits TMA3 and TMA2 of timer mode register
A (TMA).
Rev. 4.00, 03/04, page 71 of 400