HD404339 Datasheet, PDF (24/80 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer with large-capacity memory

HD404339 Series
The MCU automatically provides an oscillation stabilization period t_RC when operation switches from
watch mode to active mode. The interrupt frame period T and one of three values for t_RC can be selected
with the miscellaneous register (MIS: $00C), as listed in figure 14.
Operation can switch directly from subactive mode to active mode, as illustrated in figure 15. In this case,
the transition time T_D obeys the following relationship.
t_RC < T_D < T + t_RC
Miscellaneous register (MIS: $00C)
Bit
Initial value
Read/Write
Bit name
3
0
W
MIS3
2
0
W
MIS2
1
0
W
MIS1
0
0
W
MIS0
MIS3 MIS2
Buffer control.
Refer to figure 24.
MIS1
0
0
1
1
MIS0
0
1
0
1
T^*1
t_RC^*1
Oscillation Circuit Conditions
0.24414 ms 0.12207 ms External clock input
0.24414 ms^*2
15.625 ms 7.8125 ms Ceramic oscillator
125 ms
62.5 ms
Crystal oscillator
Not used
—
Notes: 1. The values of T and t_RC are applied when a 32.768-kHz crystal oscillator is used.
2. The value is applied only when direct transfer operation is used.
Figure 14 Miscellaneous Register
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