Epson S1C17M01 Technical Manual page 29

Clock external output (FOUT)
The FOUT pin can output the clock generated by a clock source or its divided clock to outside the IC. This al-
lows monitoring the oscillation frequency of the oscillator circuit or supplying an operating clock to external
ICs. Follow the procedure shown below to start clock external output.
1. Assign the FOUT function to the port. (Refer to the "I/O Ports" chapter.)
2. Configure the following CLGFOUT register bits:
- CLGFOUT.FOUTSRC[1:0] bits
- CLGFOUT.FOUTDIV[2:0] bits
- Set the CLGFOUT.FOUTEN bit to 1.
IOSC oscillation auto-trimming function
The auto-trimming function adjusts the IOSCCLK clock frequency by trimming the clock with reference to the
high precision OSC1CLK clock generated by the OSC1 oscillator circuit. Follow the procedure shown below to
enable the auto-trimming function.
1. After enabling the OSC1 oscillation, check if the stabilized clock is supplied (CLGINTF.OSC1STAIF bit = 1).
2. After enabling the IOSC oscillation, check if the stabilized clock is supplied (CLGINTF.IOSCSTAIF bit = 1).
3. Write 0x0096 to the MSCPROT.PROT[15:0] bits. (Remove system protection)
4. If the SYSCLK clock source is IOSC, set the CLGSCLK.CLKSRC[1:0] bits to a value other than 0x0
(IOSC).
5. Write 1 to the CLGINTF.IOSCTEDIF bit.
6. Write 1 to the CLGINTE.IOSCTEDIE bit.
7. Write 1 to the CLGIOSC.IOSCSTM bit.
8. Write a value other than 0x0096 to the MSCPROT.PROT[15:0] bits. (Set system protection)
9. The trimmed IOSCCLK can be used if the CLGINTF.IOSCTEDIF bit = 1 after an interrupt occurs.
After the trimming operation has completed, the CLGIOSC.IOSCSTM bit automatically reverts to 0. Although
the triming time depends on the temperature, an average of several 10 ms is required. When IOSCCLK is being
used as the system clock or a peripheral circuit clock, do not use the auto-trimming function.
OSC1 oscillation stop detection function
The oscillation stop detection function restarts the OSC1 oscillator circuit when it detects oscillation stop under
adverse environments that may stop the oscillation. Follow the procedure shown below to enable the oscillation
stop detection function.
1. After enabling the OSC1 oscillation, check if the stabilized clock is supplied (CLGINTF.OSC1STAIF bit =
1).
2. Write 1 to the CLGINTF.OSC1STPIF bit.
3. Write 1 to the CLGINTE.OSC1STPIE bit.
4. Write 0x0096 to the MSCPROT.PROT[15:0] bits. (Remove system protection)
5. Set the following CLGOSC1 register bits:
- Set the CLGOSC1.OSDRB bit to 1.
- Set the CLGOSC1.OSDEN bit to 1.
6. Write a value other than 0x0096 to the MSCPROT.PROT[15:0] bits. (Set system protection)
7. The OSC1 oscillation stops if the CLGINTF.OSC1STPIF bit = 1 after an interrupt occurs.
If the CLGOSC1.OSDRB bit = 1, the hardware restarts the OSC1 oscillator circuit.
Note: Enabling the oscillation stop detection function increase the oscillation stop detector current
(I ).
OSD1
S1C17M01 TECHNICAL MANUAL
(Rev. 1.2)
(Select clock source)
(Set clock division ratio)
(Enable clock external output)
(Clear interrupt flag)
(Enable interrupt)
(Enable IOSC oscillation auto-trimming)
(Clear interrupt flag)
(Enable interrupt)
(Enable OSC1 restart function)
(Enable oscillation stop detection function)
Seiko Epson Corporation
2 POWER SUPPLY, RESET, AND CLOCKS
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