
21 R/F CONVERTER (RFC)
21-10
Seiko Epson Corporation
S1C17705 TECHNICAL MANUAL
D[3:2]
CLKSRC[1:0]: RFC Clock Source Select Bits
Select the count clock source.
8.3 RFC Clock Source Selection
Table 21.
CLKSRC[1:0]
Clock source
0x3
Reserved
0x2
OSC3
0x1
OSC1
0x0
IOSC
(Default: 0x1)
D1
Reserved
D0
CLKEN: Clock Enable Bit
Enables or disables the TCCLK clock supply.
1 (R/W): Enabled (on)
0 (R/W): Disabled (off) (default)
The CLKEN default setting is 0, which disables the clock supply. Setting CLKEN to 1 sends the clock
selected to the R/F converter.
RFC Control Register (RFC_CTL)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
RFC Control
Register
(RFC_CTL)
0x53a0
(16 bits)
D15–8 –
reserved
–
0 when being read.
D7
CONEN
Continuous oscillation enable
1 Enable
0 Disable
0
R/W
D6
EVTEN
Event counter mode enable
1 Enable
0 Disable
0
R/W
D5–4 SMODE[1:0] Sensor oscillation mode select
SMODE[1:0]
Sensor
0x0 R/W
0x3
0x2
0x1
0x0
reserved
DC capacitive
AC resistive
DC resistive
D3–2 –
reserved
–
0 when being read.
D1
CHSEL
Conversion channel select
1 Ch.1
0 Ch.0
0
R/W
D0
RFCEN
RFC enable
1 Enable
0 Disable
0
R/W
D[15:8]
Reserved
D7
CONEN: Continuous Oscillation Enable Bit
Enables continuous oscillation by disabling the automatic CR oscillation stop function.
1 (R/W): Continuous oscillation enabled
0 (R/W): Continuous oscillation disabled (default)
Setting 1 to CONEN disables the reference oscillation/sensor oscillation stop conditions so that the CR
oscillator will continue oscillating. Set SREF (reference oscillation), SSENA (sensor A oscillation), or
SSENB (sensor B oscillation) in the RFC_TRG register to 1 to start oscillation even in this mode, and
set to 0 to stop oscillation.
Using this function with the CR oscillation monitoring function helps easily measure the CR oscillation
clock frequency.
D6
EVTEN: Event Counter Mode Enable Bit
Enables external clock input mode (event counter mode).
1 (R/W): External clock input mode
0 (R/W): Normal mode (default)
Setting EVTEN to 1 enables the external clock input to the RFINx pin. SREF (reference oscillation),
SSENA (sensor A oscillation), or SSENB (sensor B oscillation) should be used to control starting oscil-
lation (starting conversion) to perform converting operation even in this mode.
Note: Do not input an external clock before setting EVTEN to 1. The RFINx pin is pulled down to VSS
when the pin function is switched for the R/F converter.
D[5:4]
SMODE[1:0]: Sensor Oscillation Mode Select Bits
Select an oscillation mode.