
III PERIPHERAL BLOCK: SERIAL INTERFACE
S1C33L01 FUNCTION PART
EPSON
B-III-8-3
Setting Transfer Mode
The transfer mode of the serial interface can be set using SMDx[1:0] individually for each channel as shown in Table
8.2 below.
Table 8.2
Transfer Mode
SMDx1
SMDx0
Transfer mode
1
8-bit asynchronous mode
1
0
7-bit asynchronous mode
0
1
Clock-synchronized slave mode
0
Clock-synchronized master mode
At initial reset, SMDx becomes indeterminate, so be sure to initialize it in the software.
When using the IrDA interface, set the transfer mode for the asynchronous 7-bit or asynchronous 8-bit mode.
The input/output pins are configured differently, depending on the transfer mode. The pin configuration in each
mode is shown in Table 8.3.
Table 8.3
Pin Configuration by Transfer Mode
Transfer mode
SINx (P00/P04)
SOUTx (P01/P05)
#SCLKx (P02/P06)
#SRDYx (P03/P07)
8-bit asynchronous
Data input
Data output
Clock input/P port
P port
7-bit asynchronous
Data input
Data output
Clock input/P port
P port
Clock-synchronized slave
Data input
Data output
Clock input
Ready output
Clock-synchronized
master
Data input
Data output
Clock output
Ready input
All four pins are used in the clock-synchronized mode.
In the asynchronous mode, since #SRDYx is unused, P03 (or P07) can be used as an I/O (P) port. In addition, when an
external clock is not used, P02 (or P06) can also be used as an I/O port.
The I/O control and data registers for the I/O ports used in the serial interface can be used as general-purpose
read/write registers.
Note: To enable the IrDA interface to be set, IRMDx[1:0] (D[1:0]) / Serial I/F Ch.0 IrDA register (0x401E4)
or Serial I/F Ch.1 IrDA register (0x401E9) is provided. Since these bits become indeterminate at
initial reset, be sure to initialize them by writing "00" when using as the normal interface or "10"
when using as the IrDA interface.