HD404849 Datasheet, PDF (43/127 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404849 Series
System clock select register (SSR: $029)
Bit
Initial value
Read/Write
Bit name
3
0
W
SSR3*
2
0
W
SSR2
1
0
W
SSR1
0
—
—
Not used
SSR3
0
1
32-kHz oscillation stop
Oscillation operates in stop mode
Oscillation stops in stop mode
SSR1
0
1
System oscillation frequency selection
0.4 MHz – 1.0 MHz
1.6 MHz – 4.5 MHz
SSR2
0
1
32-kHz oscillation division
ratio selection
f_SUB = f_X/8
f_SUB = f_X/4
Note: * SSR3 is cleared only by a RESET input. SSR3 will not be cleared by a STOPC input during
stop mode, and will retain its value.
SSR3 will also not be cleared upon entering stop mode.
Figure 26 System Clock Select Register
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