2 POWER SUPPLY, RESET, AND CLOCKS
S1C17M20/M21/M22/M23/M24/M25
Seiko Epson Corporation
2-9
TECHNICAL MANUAL (Rev. 1.0)
(2) CLGOSC1.OSC1BUP bit = 1 (startup boosting operation enabled)
Normal operation
Startup boosting
operation
INV1N[1:0] setting gain
INV1B[1:0] setting gain
Oscillator circuit enable
(CLGOSC.OSC1EN)
Oscillation inverter
Oscillation waveform
Figure 2.3.4.2 Operation Example when the OSC1 Crystal Oscillation Startup Control Circuit is Used
Oscillation start procedure for the IOSC oscillator circuit
Follow the procedure shown below to start oscillation of the IOSC oscillator circuit.
1. Write 1 to the CLGINTF.IOSCSTAIF bit. (Clear interrupt flag)
2. Write 1 to the CLGINTE.IOSCSTAIE bit. (Enable interrupt)
3. Write 1 to the CLGOSC.IOSCEN bit.
(Start oscillation)
4. IOSCCLK can be used if the CLGINTF.IOSCSTAIF bit = 1 after an interrupt occurs.
Oscillation start procedure for the OSC1 oscillator circuit
Follow the procedure shown below to start oscillation of the OSC1 oscillator circuit.
1. Write 1 to the CLGINTF.OSC1STAIF bit.
(Clear interrupt flag)
2. Write 1 to the CLGINTE.OSC1STAIE bit.
(Enable interrupt)
3. Write 0x0096 to the MSCPROT.PROT[15:0] bits. (Remove system protection)
4. Configure the following CLGOSC1 register bits:
- CLGOSC1.OSC1SELCR bit
(Select oscillator type)
- CLGOSC1.OSC1WT[1:0] bits
(Set oscillation stabilization waiting time)
In addition to the above, configure the following bits when using the crystal oscillator:
- CLGOSC1.INV1N[1:0] bits
(Set oscillation inverter gain)
- CLGOSC1.CGI1[2:0] bits
(Set internal gate capacitor)
- CLGOSC1.INV1B[1:0] bits
(Set oscillation inverter gain for startup boosting period)
- CLGOSC1.OSC1BUP bit
(Enable/disable oscillation startup control circuit)
5. Write a value other than 0x0096 to the MSCPROT.PROT[15:0] bits. (Set system protection)
6. Write 1 to the CLGOSC.OSC1EN bit.
(Start oscillation)
7. OSC1CLK can be used if the CLGINTF.OSC1STAIF bit = 1 after an interrupt occurs.
The setting values of the CLGOSC1.INV1N[1:0], CLGOSC1.CGI1[2:0], CLGOSC1.OSC1WT[1:0], and
CLGOSC1.INV1B[1:0] bits should be determined after performing evaluation using the populated circuit board.
Note: Make sure the CLGOSC.OSC1EN bit is set to 0 (while the OSC3 oscillation is halted) when
switching the oscillator within two types.
Oscillation start procedure for the OSC3 oscillator circuit
Follow the procedure shown below to start oscillation of the OSC3 oscillator circuit.
1. Write 1 to the CLGINTF.OSC3STAIF bit.
(Clear interrupt flag)
2. Write 1 to the CLGINTE.OSC3STAIE bit.
(Enable interrupt)
3. Write 0x0096 to the MSCPROT.PROT[15:0] bits. (Remove system protection)
4. Configure the following CLGOSC3 register bits:
- CLGOSC3.OSC3MD bit
(Select oscillator type)
- CLGOSC3.OSC3WT[2:0] bits
(Set oscillation stabilization waiting time)
In addition to the above, configure the following bits when using the crystal/ceramic oscillator:
- CLGOSC3.OSC3INV[1:0] bits
(Set oscillation inverter gain)
Configure the following bits when using the internal oscillator:
- CLGOSC3.OSC3FQ[1:0] bits
(Select oscillation frequency)