7 OSCillaTiOn CiRCuiT anD ClOCK COnTROl
S1C63003/004/008/016 TeChniCal Manual
Seiko epson Corporation
7-5
(Rev. 1.1)
i/O Memory for Oscillation Circuit/Clock Output Control
7.6
Table 7.6.1 shows the I/O address and the control bits for the oscillation circuit and FOUT output.
6.1 Control bits of oscillation circuit/FOUT
Table 7.
Address
Register name R/W Default
Setting/data
Function
FF00H D3
ClKChG
R/W
0
1 OSC3
0 OSC1
CPU clock switch
D2
OSCC
R/W
0
1 On
0 Off
OSC3 oscillation On/Off
D1 0 (
*
3)
R
– (
*
2)
–
Unused
D0 0 (
*
3)
R
– (
*
2)
–
Unused
FF10H D3
FOuT3
R/W
0
F f
3
B f
3
/16
7 f
1
3 f
1
/32
FOUT frequency selection
(f
1
= f
OSC1
, f
3
= f
OSC3
)
D2
FOuT2
R/W
0
E f
3
/2
A f
3
/32
6 f
1
/2
2 f
1
/64
D1
FOuT1
R/W
0
D f
3
/4
9 f
3
/64
5 f
1
/4
1 f
1
/256
D0
FOuT0
R/W
0
C f
3
/8
8 f
3
/256 4 f
1
/16
0 Off
*
1 Initial value at initial reset
*
2 Not set in the circuit
*
3 Constantly "0" when being read
*
4 Unused in the S1C63003/004/008
*
5 Unused in the S1C63003/004
*
6 Unused in the S1C63003
OSCC: OSC3 oscillation control register (FF00h•D2)
Turns the OSC3 oscillation circuit on and off.
When "1" is written: OSC3 oscillation On
When "0" is written: OSC3 oscillation Off
Reading: Valid
When it is necessary to operate the CPU at high speed, set OSCC to "1." At other times, set it to "0" to reduce
current consumption. At initial reset, this register is set to "0."
ClKChG: CPu system clock switching register (FF00h•D3)
The CPU's operation clock is selected with this register.
When "1" is written: OSC3 clock is selected
When "0" is written: OSC1 clock is selected
Reading: Valid
When the CPU clock is to be OSC3, set CLKCHG to "1"; for OSC1, set CLKCHG to "0." At initial reset, this
register is set to "0."
FOuT[3:0]: FOuT frequency select register (FF10h)
Selects the frequency of the FOUT signal and controls the FOUT output.
6.2 FOUT clock frequency
Table 7.
FOUT[3:0]
FOUT frequency
FH
f
OSC3
EH
f
OSC3
/ 2
DH
f
OSC3
/ 4
CH
f
OSC3
/ 8
BH
f
OSC3
/ 16
AH
f
OSC3
/ 32
9H
f
OSC3
/ 64
8H
f
OSC3
/ 256
7H
f
OSC1
(32 kHz)
6H
f
OSC1
/ 2 (16 kHz)
5H
f
OSC1
/ 4 (8 kHz)
4H
f
OSC1
/ 16 (2 kHz)
3H
f
OSC1
/ 32 (1 kHz)
2H
f
OSC1
/ 64 (512 Hz)
1H
f
OSC1
/ 256 (128 Hz)
0H
Off
f
OSC1
: OSC1 oscillation frequency. ( ) indicates the clock frequency when f
OSC1
= 32 kHz.
f
OSC3
: OSC3 oscillation frequency
Selecting an FOUT frequency (writing 1H–FH to this register) outputs the FOUT signal from the FOUT (P13)
terminal. Set FOUT[3:0] to "0" to use P13 as a general-purpose input/output port. At initial reset, this register is
set to "0."