SIC63616-(Rev. 1.0) NO. P150
3240-0412
4.13.2 Controlling clock manager
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. The R/f converter clock can be selected from seven types (the above six clocks and the
programmable timer 1 output clock). Use the RFCKS0–RFCKS2 register to select one of them as shown in
Table 4.13.2.1.
Table 4.13.2.1 R/f converter clock frequencies
RFCKS2
1
1
1
1
0
0
0
0
RFCKS1
1
1
0
0
1
1
0
0
RFCKS0
1
0
1
0
1
0
1
0
R/f converter clock
f
OSC3
/ 4
f
OSC3
/ 2
f
OSC3
/ 1
Programmable timer 1
f
OSC1
/ 4 (8 kHz)
f
OSC1
/ 2 (16 kHz)
f
OSC1
/ 1 (32 kHz)
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 operat-
ing the serial interface. Refer to Section 4.9, "Programmable Timer" for controlling the programmable timer.
If it is not necessary to run the R/f converter, stop the clock supply by setting RFCKS0–RFCKS2 to "000B" to
reduce current consumption.
4.13.3 Connection terminals and CR oscillation circuit
The R/f converter channel 0 input/output terminals and the RFOUT output terminal are shared with the
I/O port (P00–P03), and the terminal functions must be switched with software when using these terminals
for the R/f converter.
By setting the ERF0–ERF1 register to other than "00B", P00, P01 and P02 are configured as the RFIN0, REF0
and SEN0 terminals, respectively.
The RFOUT output through the P03 port is effective when "1" is written to the RFOUT register. When the
RFOUT register is "0", P03 is used as an I/O port.
The table below lists the correspondence between the P00 to P03 terminals and the R/f converter input/
output.
Table 4.13.3.1 Setting input/output terminal functions
Terminal name
P00
P01
P02
P03
R/f converter input/output
RFIN0
REF0
SEN0
RFOUT
Note: At initial reset, P00 to P03 are configured as the I/O ports.
When using the R/f converter channel 0, switch the terminal functions (ERF0–ERF1 = "01B", RFOUT
= "1") in the initialize routine.