16 R/F COnVeRTeR
S1C63003/004/008/016 TeChniCal Manual
Seiko epson Corporation
16-1
(Rev. 1.1)
R/F Converter
16
Configuration of R/F Converter
16.1
The S1C63003/004/008/016 has a built-in CR oscillation type R/F converter that can be used as an A/D converter.
Two systems (channel 0 and channel 1) of CR oscillation circuits are built into the 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 (Resistor/Frequency) conversion circuit using a DC bias resistive sensor such as a thermistor,
and channel 1 can be used as an R/F conversion circuit the same as channel 0, or for an AC bias resistive sensor such
as a humidity sensor. The channel to be used and sensor type for channel 1 are selected with 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 measurement 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 16.1.1.
V
DD
V
SS
OSC3 oscillation
circuit (f
OSC3
)
OSC1 oscillation
circuit (f
OSC1
)
R/F converter
clock (f
TCCLK
)
Measurement
counter
clock (f
MCCLK
)
REF0
(P52)
SEN0
(P51)
RFIN0
(P53)
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
OVTC
OVMC
MC00
–MC03
MC04
–MC07
MC08
–MC11
RFRUNR
RFRUNS
Clock
manager
Measurement
counter control
Channel
control circuit
MC12
–MC15
Time base
counter
control
TC00
–TC03
TC04
–TC07
TC08
–TC11
TC12
–TC15
MC16
–MC19
TC16
–TC19
RFOUT
(P50)
RFCKS[2:0]
ERF[1:0]
Programmable timer 1
underflow signal
*
*
Not supported in the S1C63003
1.1 Configuration of R/F converter
Figure 16.
Note: When using R/F converter channel 1, be sure to select all the HUD, SEN1, REF1 and RFIN1 pins
by mask options for switching between the R/F converter pins and SEG pins. When the SEG pin is
selected, channel 1 may not operate properly even if the HUD pin is not used.
Controlling Operating Clock
16.2
The R/F converter uses the clock supplied from the clock manager as its operating clock and the count clock for the
time base counter. The clock manager generates six R/F converter clocks by dividing the OSC1 and OSC3 clocks. In
the S1C63003, the R/F converter clock can be selected from the above six clocks. In the S1C63004/008/016, it can
be selected from seven types (the above six clocks and the programmable timer 1 output clock). Use the RFCKS[2:0]
register to select one of them as shown in Table 16.2.1.