2 POWER SUPPLY, RESET, AND CLOCKS
2-16
Seiko Epson Corporation
S1C17M20/M21/M22/M23/M24/M25
TECHNICAL MANUAL (Rev. 1.0)
Table 2.6.3 SYSCLK Clock Source and Division Ratio Settings
CLGSCLK.
CLKDIV[1:0] bits
CLGSCLK.CLKSRC[1:0] bits
0x0
0x1
0x2
0x3
IOSCCLK
OSC1CLK
OSC3CLK
EXOSCCLK
0x3
1/8
Reserved
1/8
Reserved
0x2
1/4
Reserved
1/4
Reserved
0x1
1/2
1/2
1/2
Reserved
0x0
1/1
1/1
1/1
1/1
CLG Oscillation Control Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
CLGOSC
15–12 –
0x0
–
R
–
11 EXOSCSLPC
1
H0
R/W
10 OSC3SLPC
1
H0
R/W
9
OSC1SLPC
1
H0
R/W
8
IOSCSLPC
1
H0
R/W
7–4 –
0x0
–
R
3
EXOSCEN
0
H0
R/W
2
OSC3EN
0
H0
R/W
1
OSC1EN
0
H0
R/W
0
IOSCEN
1
H0
R/W
Bits 15–12 Reserved
Bit 11
EXOSCSLPC
Bit 10
OSC3SLPC
Bit 9
OSC1SLPC
Bit 8
IOSCSLPC
These bits control the clock source operations in SLEEP mode.
1 (R/W): Stop clock source in SLEEP mode
0 (R/W): Continue operation state before SLEEP
Each bit corresponds to the clock source as follows:
CLGOSC.EXOSCSLPC bit: EXOSC clock input
CLGOSC.OSC3SLPC bit: OSC3 oscillator circuit
CLGOSC.OSC1SLPC bit: OSC1 oscillator circuit
CLGOSC.IOSCSLPC bit: IOSC oscillator circuit
Bits 7–4
Reserved
Bit 3
EXOSCEN
Bit 2
OSC3EN
Bit 1
OSC1EN
Bit 0
IOSCEN
These bits control the clock source operation.
1(R/W): Start oscillating or clock input
0(R/W): Stop oscillating or clock input
Each bit corresponds to the clock source as follows:
CLGOSC.EXOSCEN bit: EXOSC clock input
CLGOSC.OSC3EN bit: OSC3 oscillator circuit
CLGOSC.OSC1EN bit: OSC1 oscillator circuit
CLGOSC.IOSCEN bit: IOSC oscillator circuit