SIC63616-(Rev. 1.0) NO. P124
3240-0412
Table 4.10.4.1 Mode settings and configurations of serial interface terminals
ESIF
1
1
1
1
1
1
1
1
1
1
1
0
P20 terminal
SCLK (O)
SCLK (O)
SCLK (O)
SCLK (O)
SCLK (I)
SCLK (I)
SCLK (I)
SCLK (I)
SCLK (I)
SCLK (I)
P20 (I/O)
P21 terminal
SOUT (O)
SOUT (O)
P21 (I/O)
P21 (I/O)
SOUT (O)
P21 (I/O)
SOUT (O)
P21 (I/O)
SOUT (O)
P21 (I/O)
P21 (I/O)
P22 terminal
SIN (I)
SIN (I)
SIN (I)
SIN (I)
SIN (I)
SIN (I)
SIN (I)
SIN (I)
SIN (I)
SIN (I)
P22 (I/O)
P23 terminal
P23 (I/O)
P23 (I/O)
P23 (I/O)
P23 (I/O)
SRDY (O)
SRDY (O)
P23 (I/O)
P23 (I/O)
SS (I)
SS (I)
P23 (I/O)
SMOD
1
1
1
1
1
0
0
0
0
0
0
*
ENCS
1
*
0
*
0
1
1
0
0
1
1
*
ESREADY
1
0
1
0
1
1
1
*
*
0
0
*
ESOUT
*
1
1
0
0
1
0
1
0
1
0
*
Mode
Master mode
Slave mode
SPI slave mode
Serial I/F not used
Prohibited
4.10.5 Setting synchronous clock
Controlling clock manager
When the serial interface is used in master mode, it uses the internal clock supplied from the clock
manager as the synchronous clock for serial transfer. The clock manager generates six serial interface
clocks by dividing the OSC1 or OSC3 clock. The synchronous clock used in master mode can be selected
from seven types (the above six clocks and the programmable timer 1 output clock). Use the SIFCKS0–
SIFCKS2 register to select one of them as shown in Table 4.10.5.1.
Table 4.10.5.1 Serial interface clock frequencies
SIFCKS2
1
1
1
1
0
0
0
0
SIFCKS1
1
1
0
0
1
1
0
0
SIFCKS0
1
0
1
0
1
0
1
0
SIF clock (master mode)
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 (slave mode) *
f
OSC1
: OSC1 oscillation frequency. ( ) indicates the frequency when f
OSC1
= 32 kHz.
f
OSC3
: OSC3 oscillation frequency
∗
The maximum clock frequency is limited to 1 MHz.
When programmable timer 1 is selected, the programmable timer 1 underflow signal is divided by 2 be-
fore it is used as the synchronous clock. In this case, the programmable timer must be controlled before
operating the serial interface. Refer to Section 4.9, "Programmable Timer" for controlling the program-
mable timer.
Fix SIFCKS0–SIFCKS2 at "000B" in slave mode.
At initial reset, "internal clock Off (slave mode)" is selected.
Selecting the synchronous clock format
The format (polarity and phase) of the synchronous clock for the serial interface can be configured using
the SCPS0–SCPS1 register.
Table 4.10.5.2 Configuration of synchronous clock format
SCPS1
1
1
0
0
SCPS0
1
0
1
0
Polarity
Negative (SCLK)
Negative (SCLK)
Positive (SCLK)
Positive (SCLK)
Phase
Rising edge ( )
Falling edge ( )
Falling edge ( )
Rising edge ( )
At initial reset, the clock polarity is set to positive and the phase is set to the rising edge.
See Figure 4.10.6.2 for the data transfer timings by the synchronous clock format selected.