HD404459 Datasheet, PDF (43/122 Pages) Renesas Technology Corp – 4-bit HMCS400-series microcomputers

System clock select register 1 (SSR1: $029)
Bit
Initial value
Read/Write
Bit name
3
0
W
SSR13*
2
0
W
SSR12
1
0
0
—
W
—
SSR11 Not used
HD404459 Series
SSR11
0
1
System oscillation frequency selection
1.6 to 4.0 MHz
0.4 to 1.0 MHz
SSR12
0
1
32-kHz oscillation division ratio selection
f_sub = fx/8
f_sub = fx/4
SSR13
0
1
32-kHz oscillation stop
Oscillation operates in stop mode
Oscillation stops in stop mode
Note: * SSR13 is reset to 0 only by RESET input. When STOPC is input in stop mode, SSR13
is not reset but retains its value. SSR13 is not reset in stop mode.
Figure 26 System Clock Select Register 1 (SSR1: $029)
System clock select register 2 (SSR2: $02A)
Bit
Initial value
Read/Write
Bit name
3
2
1
—
—
0
—
—
W
Not used Not used SSR21
0
0
W
SSR20
SSR21 SSR20
0
0
1
1
0
1
System clock division ratio selection
1/4
1/8
1/16
1/32
Figure 27 System Clock Select Register 2 (SSR2: $02A)
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