S1C63666 TECHNICAL MANUAL
EPSON
111
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (R/f Converter)
4.15 R/f Converter
4.15.1 Configuration of R/f converter
The S1C63666 has CR oscillation type R/f converter.
A CR oscillation circuit is built into this R/f converter, so it is possible to compose an R/f conversion
circuit by connecting a resistive sensor, reference resistance and a capacitor.
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 measurement circuits using a thermistor can be easily
realized using this R/f converter. Two sensors can be connected.
The configuration of the R/f converter is shown in Figure 4.15.1.1.
REF
V
DD
V
SS
SEN0
SEN1
RFIN
Interrupt
request
CR oscillation control circuit
Measurement counter
Time base counter
Data bus
Interrupt
control
circuit
OVTBC
OVMC
MC00
~MC03
MC04
~MC07
MC08
~MC11
OSC1
oscillation
circuit
f
OSC1
RFRUNS
RFRUNR
MC12
~MC15
Time base
counter
control
circuit
TC00
~TC03
TC04
~TC07
TC08
~TC11
TC12
~TC15
MC16
~MC19
TC16
~TC19
RFOUT
Fig. 4.15.1.1 Configuration of R/f converter
4.15.2 Connection terminals and CR oscillation circuit
The S1C63666 has the connecting terminals that can configure an R/f converter with a reference resis-
tance and two sensors. Figure 4.15.2.1 shows the connection diagram of external elements.
The R/f conversion circuit supports two sensor inputs by switching the sensor. The sensor to be used can
be selected by the SENSEL register. Writing "0" to SENSEL selects sensor 0 and writing "1" selects sensor 1.
V
SS
REF
SEN1
SEN0
RFIN
Sensor 0
Sensor 1
Reference resistance
R
SEN0
R
SEN1
R
REF
C
RF
R
SEN0
, R
SEN1
R
REF
C
RF
: Resistive sensor
: Reference resistance
: Capacitor
Fig. 4.15.2.1 R/f converter external connection diagram