
348
Bit 3—Subsystem Clock Stop Setting (SSR13): Selects whether the subsystem clock (32.768
kHz) operates or stops in stop mode.
This bit is initialized to 0 only on reset.
SSR13
Description
0
The subsystem clock operates in stop mode
(initial value)
1
The subsystem clock stops in stop mode
Bit 2—Subsystem Clock Divisor Switch (SSR12): Specifies the divisor for the subsystem clock
that is supplied to the CPU and the built-in peripheral modules in subactive mode. However, note
that the divisor for the subsystem clock supplied to PSW is fixed at eight, i.e., f
W = fX/8. Thus the
clock used for timer A in clock time base mode is not affected by the setting of this bit.
This bit must be set in active mode. The microcomputer may operate incorrectly if this bit is
changed in subactive mode. Also, note that this bit is initialized to 0 on reset and in stop mode.
SSR12
Description
0f
SUB will be 1/8 of the subsystem clock oscillator frequency fX (fSUB = fX/8) and the
CPU single instruction cycle time will be 244.14 s (when f
X = 32.768 kHz).
(initial value)
1f
SUB will be 1/4 of the subsystem clock oscillator frequency fX (fSUB = fX/4) and the
CPU single instruction cycle time will be 122.07 s (when f
X = 32.768 kHz).
Bit 1—System Clock Selection (SSR11): The SSR11 bit must be set to match the frequency of
the system clock.
This bit is initialized to 0 on reset and in stop mode.
SSR11
Description
0
The system clock frequency is between 0.4 and 1.0 MHz
(initial value)
1
The system clock frequency is between 1.6 and 4.5 MHz (HD404339 Series)
The system clock frequency is between 1.6 and 5.0 MHz (HD404369 Series)*
1
The system clock frequency is between 1.6 and 8.5 MHz (HD404369 Series)*
2
Notes: If these register settings do not match the frequency of the system oscillator, the
subsystem using the 32 kHz oscillator will not operate correctly. If the subsystem clock is
used, then the system clock frequency must either be between 0.4 and 1.0 MHz or
between 1.6 and 4.5 MHz (or 1.6 and 5.0 MHz, or 1.6 and 8.5 MHz).
1. HD404364, HD404368, HD4043612, HD404369
2. HD40A4364, HD40A4368, HD40A43612, HD40A4369, HD407A4369