Setting Transfer Mode - Epson CMOS 32-Bit Single Chip Microcomputer S1C33L03 Technical Manual

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.
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.
Transfer mode
8-bit asynchronous
7-bit asynchronous
Clock-synchronized slave
Clock-synchronized
master
All four pins are used in the clock-synchronized mode.
In the asynchronous mode, since #SRDYx is unused, P03 (or P07, P24, P23) can be used as an I/O (P) port. In
addition, when an external clock is not used, P02 (or P06, P25, P15) 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 IrDA register (Ch.0:
0x401E4, Ch.1: 0x401E9, Ch.2: 0x401F4, Ch.3: 0x401F9) 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.
S1C33L03 FUNCTION PART
Table 8.2 Transfer Mode
SMDx1 SMDx0
1 1 8-bit asynchronous mode
1 0 7-bit asynchronous mode
0 1 Clock-synchronized slave mode
0 0 Clock-synchronized master mode
Table 8.3 Pin Configuration by Transfer Mode
SINx SOUTx
Data input Data output
Data input Data output
Data input Data output
Data input Data output
EPSON
III PERIPHERAL BLOCK: SERIAL INTERFACE
Transfer mode
#SCLKx
Clock input/P port
Clock input/P port
Clock input
Clock output
A-1
#SRDYx
P port
P port
Ready output
Ready input
B-III
SIF
B-III-8-3