SN8P2318 Series
C-type LCD, RFC 8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 98
Version 1.5
9
9
9
RESISTANCE TO FREQURNCY
CONVERTER (RFC)
9.1 OVERVIEW
The MCU builds in resistance to frequency converter (RFC) CR type oscillation converter. The RFC conversion circuit
is connecting a resistive sensor, reference resistance and a capacitor. Resistance value of the resistive sensor or
reference resistance connected to the RFC channel input is converted into frequency by CR oscillator and the number
of clocks is counted in the built-in measurement timer/counter (T1). Reading the value of T1 measurement obtains the
digitally converting value detected by the resistance. Various sensor circuits such as temperature measurement using
a thermistor can easily realize using the RFC. The RFC includes 5 channels. One channel is used reference channel,
and the other channels are sensor input channels. For different resistive sensor, the RFC clock frequency is different.
T1 provides pulse width measurement and input frequency measurement functions to measure high/low speed RFC
clock. RFC pin is shared with port 1. When RFCENB = 1, P1.0~P1.4 are selected to RFC0~RFC4 channel through
RFCH[2:0] bits. P1.6 is shared with RFCOUT pin controlled by RFCOUT bit of RFCM register. Each of RFC channels
is connected to T1capture timer function to measure RFC frequency and does RFC oscillation. These RFC pins are
shared with GPIO controlled by RFCM register. RFC function actives under green mode, but not support wake-up
function.
P1.4/RFC4
P1.3/RFC3
P1.2/RFC2
P1.1/RFC1
P1.0/RFC0
RFCENB
RFCH[2:0]
RFC
Oscillation
Generator
RFCENB
T1 Capture Timer
P1.6/RFCOUT
RFCENB
RFCOUT
RFC Channel:
RFC channels are shared with GPIO controlled by RFCENB = 1 and RFCH[2:0] selected.
RFCENB=1 is necessary, or the RFC channel selected by RFCH[2:0] is GPIO mode.
RFCOUT pin:
RFC output pin is shared with GPIO controlled by RFCOUT bit. RFC output pin outputs RFC
oscillating signal through RFC oscillator generator processing. The signal also inputs to T1 capture timer.