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2 POWER SUPPLY, RESET, AND CLOCKS
2-20
Seiko Epson Corporation
S1C31D50/D51 TECHNICAL MANUAL
(Rev. 2.00)
Bit 11–10 OSC3FQ[1:0]
These bits set the oscillation frequency of the OSC3 internal oscillator circuit.
Table 2.6.9 OSC3CLK Frequency Selection
CLGOSC3.OSC3FQ[1:0] bits
OSC3CLK frequency
0x3
16 MHz
0x2
Reserved
0x1
8 MHz
0x0
4 MHz
Bit 9
OSC3MD
This bit selects an oscillator type of the OSC3 oscillator circuit.
1 (R/WP): Crystal/ceramic oscillator
0 (R/WP): Internal oscillator
Bits 8–6
Reserved
Bits 5–4
OSC3INV[1:0]
These bits set the oscillation inverter gain when crystal/ceramic oscillator is selected as the OSC3 os-
cillator type.
Table 2.6.10 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 OSC3CLK 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: • 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.
• Be sure to avoid altering the CLGOSC3.OSC3FQ[1:0] bits while the auto-trimming is being
executed.
Bits 2–0
OSC3WT[2:0]
These bits set the oscillation stabilization waiting time for the OSC3 oscillator circuit.
Table 2.6.11 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