Operations - Epson S1C17F13 Technical Manual

2 POWER SUPPLY, RESET, AND CLOCKS
2.3.4

Operations

Oscillation start time and oscillation stabilization waiting time
The oscillation start time refers to the time after the oscillator circuit is enabled until the oscillation signal is ac-
tually sent to the internal circuits. The oscillation stabilization waiting time refers to the time it takes the clock
to stabilize after the oscillation starts. To avoid malfunctions of the internal circuits due to an unstable clock
during this period, the oscillator circuit includes an oscillation stabilization waiting circuit that can disable sup-
plying the clock to the system until the designated time has elapsed. Figure 2.3.4.1 shows the relationship be-
tween the oscillation start time and the oscillation stabilization waiting time.
Digitized oscillation waveform
Oscillator circuit output clock
Oscillation stabilization waiting completion flag
Figure 2.
The oscillation stabilization waiting times for the OSC1 (OSC1A and OSC1B) and OSC3A oscillator circuits
can be set using the CLGOSC1.OSC1WT[1:0] and CLGOSC3A.OSC3AWT[1:0] bits, respectively. Allow an
ample margin for the setting value according to the resonator type used. To check whether the oscillation sta-
bilization waiting time is set properly and the clock is stabilized immediately after the oscillation starts or not,
monitor the oscillation clock using the FOUT output function. The oscillation stabilization waiting time for the
OSC3B oscillator circuit is fixed at 128 OSC3BCLK clocks.
When the oscillation stabilization waiting operation has completed, the oscillator circuit sets the oscillation sta-
bilization waiting completion flag and starts clock supply to the internal circuits.
Note: The oscillation stabilization waiting time is always expended at start of oscillation even if the os-
cillation stabilization waiting completion flag has not be cleared to 0.
Oscillation start procedure for the OSC3B oscillator circuit
Follow the procedure shown below to start oscillation of the OSC3B oscillator circuit.
1. Write 1 to the CLGINTF.OSC3BSTAIF bit.
2. Write 1 to the CLGINTE.OSC3BSTAIE bit.
3. Write 0x0096 to the MSCPROT.PROT[15:0] bits. (Remove system protection)
4. Configure the CLGOSC3B.OSC3BFREQ bit.
5. Write a value other than 0x0096 to the MSCPROT.PROT[15:0] bits. (Set system protection)
6. Write 1 to the CLGOSC.OSC3BEN bit.
7. OSC3BCLK can be used if the CLGINTF.OSC3BSTAIF bit = 1 after an interrupt occurs.
Oscillation start procedure for the OSC3A oscillator circuit
Follow the procedure shown below to start oscillation of the OSC3A oscillator circuit.
1. Write 1 to the CLGINTF.OSC3ASTAIF bit.
2. Write 1 to the CLGINTE.OSC3ASTAIE bit.
3. Write 0x0096 to the MSCPROT.PROT[15:0] bits. (Remove system protection)
4. Configure the following CLGOSC3A register bits according to the resonator used.
- CLGOSC3A.INVN[1:0] bits
- CLGOSC3A.OSC3AWT[1:0] bits
2-8
Oscillator circuit enable
(∗OSC∗EN)
Oscillation waveform
(∗OSC∗CLK)
(∗OSC∗STAIF)
3.4.1 Oscillation Start Time and Oscillation Stabilization Waiting Time
Seiko epson Corporation
System supply waiting time
Oscillation start time
Oscillation stabilization waiting time
(Clear interrupt flag)
(Enable interrupt)
(Select frequency)
(Start oscillation)
(Clear interrupt flag)
(Enable interrupt)
(Set oscillation inverter gain)
(Set oscillation stabilization waiting time)
S1C17F13 TeChniCal Manual
(Rev. 1.0)