Cr Oscillation Frequency Monitoring Function; Interrupts - Epson S1C17W03 Technical Manual

External part tolerances
Power supply voltage fluctuations
Parasitic capacitance and resistance of the board
Temperature
Unevenness of IC quality

18.4.5 CR Oscillation Frequency Monitoring Function

The CR oscillation clock (RFCLK) generated during converting operation can be output from the RFCLKOn pin
for monitoring. By setting the RFCnCTL.CONEN bit to 1, the RFC Ch.n enters continuous oscillation mode that
disables oscillation stop conditions to continue oscillating operations. In this case, set the the RFCnTRG.SREF bit
(reference oscillation), the RFCnTRG.SSENA bit (sensor A oscillation), or the RFCnTRG.SSENB bit (sensor B os-
cillation) to 1 to start oscillation. Set the bit to 0 to stop oscillation. Using this function helps easily measure the CR
oscillation clock frequency. Furthermore, setting the RFCnCTL.RFCLKMD bit to 1 changes the output clock to the
divided-by-two RFCLK clock.
RFCnTRG.SSENA, SSENB, SREF
(RFCnCTL.RFCLKMD = 0)
(RFCnCTL.RFCLKMD = 1)

18.5 Interrupts

The RFC has a function to generate the interrupts shown in Table 18.5.1.
Interrupt
Reference oscillation RFCnINTF.EREFIF
completion
Sensor A oscillation RFCnINTF.ESENAIF
completion
Sensor B oscillation RFCnINTF.ESENBIF When sensor B oscillation has been completed normally
completion
Measurement counter RFCnINTF.OVMCIF
overflow error
Time base counter RFCnINTF.OVTCIF
overflow error
The RFC provides interrupt enable bits corresponding to each interrupt flag. An interrupt request is sent to the in-
terrupt controller only when the interrupt flag, of which interrupt has been enabled by the interrupt enable bit, is
set. For more information on interrupt control, refer to the "Interrupt Controller" chapter.
S1C17W03/W04 TECHNICAL MANUAL
(Rev. 1.2)
Table 18.4.4.1 Error Factors
Error factor
RFCnCTL.CONEN
RFINn pin
RFCLKOn pin
RFCLKOn pin
Figure 18.4.5.1 CR Oscillation Clock (RFCLK) Waveform
Table 18.5.1 RFC Interrupt Function
Interrupt flag
When reference oscillation has been completed normally
due to a measurement counter overflow
When sensor A oscillation has been completed normally
due to the time base counter reaching 0x000000
due to the time base counter reaching 0x000000
When sensor oscillation has been terminated abnormally
due to a measurement counter overflow
When reference oscillation has been terminated abnor-
mally due to a time base counter overflow
Seiko Epson Corporation
Influence
Large
Large
Middle
Small
Small
Writing 1
Set condition
18 R/F CONVERTER (RFC)
Writing 0
V
DD
V
SS
V
DD
V
SS
Clear
condition
Writing 1
Writing 1
Writing 1
Writing 1
Writing 1
18-7