
21 R/F CONVERTER (RFC)
21-8
Seiko Epson Corporation
S1C17705 TECHNICAL MANUAL
Forced Termination
21.6.4
To abort reference oscillation or sensor oscillation, write 0 to SREF (reference oscillation), SSENA (sensor A oscil-
lation), or SSENB (sensor B oscillation) in the RFC_TRG register used to start the oscillation. The counters main-
tain the value at they stopped, note, however, that the conversion results cannot be guaranteed if the oscillation is
resumed. When resuming oscillation, initialize the counters.
Conversion Error
21.6.5
Performing reference oscillation and sensor oscillation with the same resistor and capacitor results n
≈ m. The dif-
ference between n and m is a conversion error. The conversion error may be introduced caused by temperature,
voltage, and unevenness of IC quality, as well as external parts and on-board parasitic elements. For sample errors,
see “Electrical Characteristics.”
RFC Interrupts
21.7
The RFC module includes a function for generating the following five different types of interrupts.
Reference oscillation completion interrupt
Sensor A oscillation completion interrupt
Sensor B oscillation completion interrupt
Measurement counter overflow error interrupt
Time base counter overflow error interrupt
The RFC module outputs one interrupt signal shared by the five above interrupt causes to the interrupt controller
(ITC). Inspect the interrupt flag to determine the interrupt cause occurred.
Reference oscillation completion interrupt
To use this interrupt, set EREFIE/RFC_IMSK register to 1. If EREFIE is set to 0 (default), interrupt requests
for this cause will not be sent to the ITC.
When the measurement counter overflows and a reference oscillation is completed normally, the R/F converter
sets EREFIF/RFC_IFLG register to 1. If reference oscillation completion interrupts are enabled (EREFIE = 1),
an interrupt request is sent simultaneously to the ITC.
Sensor A oscillation completion interrupt
To use this interrupt, set ESENAIE/RFC_IMSK register to 1. If ESENAIE is set to 0 (default), interrupt re-
quests for this cause will not be sent to the ITC.
When the time base counter reaches 0x0 and a sensor A oscillation is completed normally, the R/F converter
sets ESENAIF/RFC_IFLG register to 1. If sensor A oscillation completion interrupts are enabled (ESENAIE =
1), an interrupt request is sent simultaneously to the ITC.
Sensor B oscillation completion interrupt
To use this interrupt, set ESENBIE/RFC_IMSK register to 1. If ESENBIE is set to 0 (default), interrupt re-
quests for this cause will not be sent to the ITC.
When the time base counter reaches 0x0 and a sensor B oscillation is completed normally, the R/F converter
sets ESENBIF/RFC_IFLG register to 1. If sensor B oscillation completion interrupts are enabled (ESENBIE =
1), an interrupt request is sent simultaneously to the ITC.
Measurement counter overflow error interrupt
To use this interrupt, set OVMCIE/RFC_IMSK register to 1. If OVMCIE is set to 0 (default), interrupt requests
for this cause will not be sent to the ITC.
When the measurement counter overflows and a sensor oscillation is terminated abnormally, the R/F converter
sets OVMCIF/RFC_IFLG register to 1. If measurement counter overflow error interrupts are enabled (OVMCIE
= 1), an interrupt request is sent simultaneously to the ITC.