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EPSON
S1C63656 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (R/f Converter)
4.14 R/f Converter
4.14.1 Configuration of R/f converter
The S1C63656 has a CR oscillation type R/f converter.
Two systems (channel 0 and channel 1) of CR oscillation circuit are built into this R/f converter, so it is
possible to compose two types of R/f conversion circuits by connecting different sensors to each CR
oscillation circuit.
Channel 0 can be used as an R/f conversion circuit using a resistive sensor such as a thermistor, and
channel 1 can be used as an R/f conversion circuit same as channel 0, or an R/f conversion circuit for
humidity conversion using a resistive humidity sensor.
The channel to be used and sensor type for channel 1 are selected using software.
Resistance value (relative value to external reference resistance) of the resistive sensor that has been
connected to the sensor input terminal is converted into frequency by the CR oscillation circuit and the
number of clocks is counted in the built-in measurement counter. By reading the value of the measure-
ment counter, it can obtain the data after digitally-converting the value detected by the sensor.
Various sensor circuits such as temperature/humidity measurement circuits can be easily realized using
this R/f converter.
The configuration of the R/f converter is shown in Figure 4.14.1.1.
V
DD
V
SS
OSC1
OSC3
REF0
SEN0
RFIN0
Interrupt
request
Ch. 0 oscillation control circuit
REF1
V
DD
V
SS
SEN1
HUD
RFIN1
Ch. 1 oscillation control circuit
Measurement counter
Time base counter
Data bus
Interrupt
control
OVTBC
OVMC
MC00
~MC03
MC04
~MC07
MC08
~MC11
Clock
selector
Input
control
Channel
control
AC, DC
control
MC12
~MC15
Time base
counter
control
TC00
~TC03
TC04
~TC07
TC08
~TC11
TC12
~TC15
MC16
~MC19
TC16
~TC19
RFOUT
Fig. 4.14.1.1 Configuration of R/f converter