25 R/F COnVeRTeR (RFC)
25-10
Seiko epson Corporation
S1C17624/604/622/602/621 TeChniCal Manual
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 RFIN
x
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 RFIN
x
pin is pulled down to V
SS
when the pin function is switched for the R/F converter.
D[5:4]
SMODe[1:0]: Sensor Oscillation Mode Select Bits
Selects an oscillation mode.
8.3 Oscillation Mode Selection
Table 25.
SMODe[1:0]
Oscillation mode
0x3
Reserved
0x2
DC oscillation mode for measuring capacitive sensors
0x1
AC oscillation mode for measuring resistive sensors
0x0
DC oscillation mode for measuring resistive sensors
(Default: 0x0)
For more information on the oscillation mode, see Section 25.4.1.
D[3:2]
Reserved
D1
ChSel: Conversion Channel Select Bit
Selects the channel to perform conversion.
1 (R/W): Ch.1
0 (R/W): Ch.0 (default)
The D[7:4] settings in this register and oscillation control using the RFC_TRG register are effective
only for the channel specified by CHSEL.
D0
RFCen: RFC enable Bit
Enables or disables the R/F converter.
1 (R/W): Enabled
0 (R/W): Disabled (default)
Setting RFCEN to 1 enables the R/F converter to start converting operations. When RFCEN is 0, ma-
nipulations of the RFC_TRG register for oscillation control are ineffective.
RFC Oscillation Trigger Register (RFC_TRG)
Register name address
Bit
name
Function
Setting
init. R/W
Remarks
RFC Oscillation
Trigger Register
(RFC_TRG)
0x53a2
(16 bits)
D15–3 –
reserved
–
–
–
0 when being read.
D2
SSenB
Sensor B oscillation control/status
1 Start/Run
0 Stop
0
R/W
D1
SSena
Sensor A oscillation control/status
1 Start/Run
0 Stop
0
R/W
D0
SReF
Reference oscillation control/status 1 Start/Run
0 Stop
0
R/W
D[15:3] Reserved