2 POWER SUPPLY, RESET, AND CLOCKS
S1C17M20/M21/M22/M23/M24/M25
Seiko Epson Corporation
2-19
TECHNICAL MANUAL (Rev. 1.0)
Bits 5–4
OSC3INV[1:0]
These bits set the oscillation inverter gain of the OSC3 crystal/ceramic oscillator circuit.
Table 2.6.9 OSC3 Oscillation Inverter Gain Setting
CLGOSC3.OSC3INV[1:0] bits
Inverter gain
0x3
Max.
0x2
↑
0x1
↓
0x0
Min.
Bit 3
OSC3STM
This bit controls the OSC3 internal oscillator auto-trimming function.
1 (WP): Start trimming
0 (WP): Stop trimming
1 (R):
Trimming is executing.
0 (R):
Trimming has finished. (Trimming operation inactivated.)
This bit is automatically cleared to 0 when trimming has finished.
Notes: • Do not use OSC3CLK as the system clock or peripheral circuit clocks while the
CLGOSC3.OSC3STM bit = 1.
• The auto-trimming function does not work if the OSC1 oscillator circuit is stopped. Make
sure the CLGINTF.OSC1STAIF bit is set to 1 before starting the trimming operation.
• Do not alter the CLGOSC3.OSC3FQ[1:0] bits while auto-trimming is being executed.
• Select the 32.768 kHz crystal oscillator for the OSC1 oscillator circuit when using the
auto-trimming function. The clock cannot be adjusted properly by the internal oscillator.
Bits 2–0
OSC3WT[2:0]
These bits set the oscillation stabilization waiting time for the OSC3 oscillator circuit.
Table 2.6.10 OSC3 Oscillation Stabilization Waiting Time Setting
CLGOSC3.OSC3WT[2:0] bits
Oscillation stabilization waiting time
0x7
65,536 clocks
0x6
16,384 clocks
0x5
4,096 clocks
0x4
1,024 clocks
0x3
256 clocks
0x2
64 clocks
0x1
16 clocks
0x0
4 clocks
CLG Interrupt Flag Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
CLGINTF
15–8 –
0x00
–
R
–
7
–
0x0
–
R
6
(reserved)
0
H0
R
5
OSC1STPIF
0
H0
R/W Cleared by writing 1.
4
OSC3TEDIF
0
H0
R/W
3
–
0
–
R
–
2
OSC3STAIF
0
H0
R/W Cleared by writing 1.
1
OSC1STAIF
0
H0
R/W
0
IOSCSTAIF
0
H0
R/W
Bits 15–6, 3 Reserved