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4.10.7 Data transfer in SPI mode
The serial interface supports serial data transfer in SPI mode.
This mode has the same serial master and slave functions and control method except that the SRDY output
cannot be used when P23 is configured to the SS terminal. Refer to Section 4.10.4, "Operating mode of serial
interface", and Section 4.10.6, "Data input/output and interrupt function", for these common descriptions.
SPI slave device
When using the S1C63616 as an SPI slave device, set the serial interface to SPI slave mode.
ESIF = "1", SMOD = "0", ENCS = "1", ESREADY = "0", ESOUT = "1" (when SOUT is used)
The P23 terminal functions as the SS (Slave Select) signal input terminal.
To perform data transfer in this mode, write "1" to SCTRG to enable the serial interface to transmit/re-
ceive data the same as the slave mode described above. The serial interface starts data transfer when
the external master device outputs the synchronous clock to the SCLK terminal after it asserts the slave
select signal (set to low) input to the SS (P23) terminal. The external device must hold the SS signal (P23
terminal) active while data is being transferred. When the SS signal is inactive, the serial interface does
not start data transfer even if the synchronous clock is input to the SCLK terminal.
SPI master device
When using the S1C63616 as an SPI master device, set the serial interface to master mode.
ESIF = "1", SMOD = "1", ENCS = "0", ESREADY = "0", ESOUT = "1" (when SOUT is used)
The SS signal output terminal is not available in master mode, set an I/O port to output mode and use
it as the SS signal output terminal. The SS signal must be set to low before writing "1" to SCTRG and
hold that active level while data is being transferred. After 8-bit data is transmitted/received, set the SS
signal to high.
Timing chart
The data transfer timing chart in SPI mode is shown in Figures 4.10.7.1 .
SCTRG (W)
SCTRG (R)
SCLK
SIN
8-bit shift register
SOUT
ISIF
SS input (Slave mode)
SS output (Master mode)
Figure 4.10.7.1 Timing chart in SPI mode (when SCPS1 = SCPS0 = "0")
Notes: • The S1C63616 serial interface does not have a transmit buffer and a receive buffer, therefore,
data transfer must be processed in every one-byte transfer. The interrupt factor flag is set after a
transfer for one byte has been completed. A start of data transfer from/to the SPI device cannot be
used as a trigger to start the interrupt handler.
• If the SS signal becomes inactive during data transfer in SPI slave mode or if the master device
outputs the SCLK signal before it asserts the SS signal, the serial interface cannot transmit/receive
data normally.
SIC63616-(Rev. 1.0) NO. P128
3240-0412
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