2-15
Seiko Epson Corporation
S1C31D50 TECHNICAL MANUAL
(Rev. 1.00)
Oscillation start procedure for the OSC3 oscillator circuit
Crystal/ceramic mode
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 SYSPROT.PROT[15:0] bits.
(Remove system protection)
4.
Configure the following CLGOSC3 register bits.
-
CLGOSC3.OSC3WT[2:0] bits
(Set oscillation stabilization waiting time)
-
CLGOSC3.OSC3INV[1:0] bits
(Set oscillation inverter gain)
-
CLGOSC3.OSC3MD bits
(Set crystal/ceramic oscillation mode)
5.
Write a value other than 0x0096 to the SYSPROT.PROT[15:0] bits.
(Set system protection)
6.
Assign the OSC3 oscillator input/output functions to the ports.
(Refer to the “I/O Ports” chapte
r.)
7.
Write 1 to the CLGOSC.OSC3EN bit.
(Start oscillation)
8.
OSC3CLK can be used if the CLGINTF.OSC3STAIF bit = 1 after an interrupt occurs.
The setting values of the CLGOSC3.OSC3INV[1:0] and CLGOSC3.OSC3WT[2:0] bits should be
determined after performing evaluation using the populated circuit board.
Internal Oscillation
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 SYSPROT.PROT[15:0] bits.
(Remove system protection)
4.
Configure the following CLGOSC3 register bits.
-
CLGOSC3.OSC3WT[2:0] bits
(Set oscillation stabilization waiting time)
-
CLGOSC3.OSC3MD bits
(Set CR oscillation mode)
5.
Write a value other than 0x0096 to the SYSPROT.PROT[15:0] bits.
(Set system protection)
6.
Write 1 to the CLGOSC.OSC3EN bit.
(Start oscillation)
7.
OSC3CLK can be used if the CLGINTF.OSC3STAIF bit = 1 after an interrupt occurs.
System clock switching
The CPU boots using IOSCCLK as SYSCLK. After booting, the clock source of SYSCLK can be switched
ac- cording to the processing speed required. The SYSCLK frequency can also be set by selecting the
clock source division ratio, this makes it possible to run the CPU at the most suitable performance
for the process to be executed. The CLGSCLK.CLKSRC[1:0] and CLGSCLK.CLKDIV[1:0] bits are used for
this control.
The CLGSCLK register bits are protected against writings by the system protect function, therefore, the
system protection must be removed by writing 0x0096 to the SYSPROT.PROT[15:0] bits before the register
setting can be altered. For the transition between the operating modes including the system clock
switching, refer to
“Operating
Mode.
”
Summary of Contents for S1C31D50
Page 461: ...25 1 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 25 Package TQFP12 48PIN ...
Page 462: ...25 2 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 QFP13 64PIN ...
Page 463: ...25 3 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 TQFP14 80PIN ...
Page 464: ...25 4 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 QFP15 100PIN ...