16 R/F COnVeRTeR
S1C63003/004/008/016 TeChniCal Manual
Seiko epson Corporation
16-9
(Rev. 1.1)
RFCKS[2:0]: R/F converter clock frequency select register (FF15h•D[2:0])
Selects the R/F converter clock frequency.
7.2 R/F converter clock frequencies
Table 16.
RFCKS[2:0]
RFC clock
7
f
OSC3
/ 4
6
f
OSC3
/ 2
5
f
OSC3
/ 1
4
Programmable timer 1
*
3
f
OSC1
/ 4 (8 kHz)
2
f
OSC1
/ 2 (16 kHz)
1
f
OSC1
/ 1 (32 kHz)
0
Off
f
OSC1
: OSC1 oscillation frequency. ( ) indicates the frequency when f
OSC1
= 32 kHz.
f
OSC3
: OSC3 oscillation frequency
When programmable timer 1* is selected, the programmable timer 1 underflow signal is divided by 2 before it
is used as the R/F converter clock. In this case, the programmable timer must be controlled before operating the
R/F converter. Refer to the "Programmable Timer" chapter for controlling the programmable timer.
If it is not necessary to run the R/F converter, stop the clock supply by setting this register to "0" to reduce current
consumption. At initial reset, this register is set to "0."
* The programmable timer 1 output clock cannot be used in the S1C63003.
eRF[1:0]: R/F conversion select register (FF60h•D[1:0])
Selects the channel and sensor type to perform R/F conversion.
7.3 Selecting channel and sensor type
Table 16.
ERF[1:0]
Channel and sensor type
3
Ch.1 DC
2
Ch.1 AC
1
Ch.0 DC
0
I/O
DC: R/F conversion using a DC bias resistive sensor such as a thermistor
AC: R/F conversion using an AC bias resistive sensor such as a humidity sensor
The R/F converter channel 0 input/output terminals are shared with the I/O port (P51–P53). By setting this reg-
ister to other than "0," P53, P52 and P51 are configured as the RFIN0, REF0 and SEN0 terminals, respectively.
At initial reset, this register is set to "0."
RFOuT: RFOuT enable register (FF60h•D2)
Enables RFOUT output from the P50 port.
When "1" is written: Enabled (RFOUT)
When "0" is written: Disabled (I/O port)
Reading: Valid
When using the RFOUT output, write "1" to RFOUT to set P50 as the RFOUT output port. At initial reset, this
register is set to "0."
RFCnT: Continuous oscillation enable register (FF60h•D3)
Enables the R/F converter to oscillate continuously.
When "1" is written: Continuous oscillation
When "0" is written: Normal oscillation
Reading: Valid
By writing "1" to RFCNT, the reference oscillation or sensor oscillation can be continued even if the stop condi-
tion has been met. This function with RFOUT enabled allows easy measurement of the CR oscillation frequency.
At initial reset, this register is set to "0."