SH7706 Datasheet, PDF (485/749 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH™ RISC engine Family/SH7700 Series

Section 15 Smart Card Interface
Switching Modes: When switching from receive mode to transmit mode, check that the receive
operation is completed before starting initialization and setting RE to 0 and TE to 1. The RDRF,
PER, and ORER flags can be used to check if reception is completed. When switching from
transmit mode to receive mode, check that the transmit operation is completed before starting
initialization and setting TE to 0 and RE to 1. The TEND flag can be used to check if transmission
is completed.
Interrupt Operation: In the smart card interface mode, there are three types of interrupts:
transmit-data-empty (TXI), communication error (ERI) and receive-data-full (RXI). In this mode,
the transmit-end interrupt (TEI) cannot be requested.
Set the TEND flag in SCSSR to 1 to request a TXI interrupt. Set the RDRF flag in SCSSR to 1 to
request an RXI interrupt. Set the ORER, PER, or FER/ERS flag in SCSSR to 1 to request an ERI
interrupt (table 15.8).
Table 15.8 Smart Card Mode Operating State and Interrupt Sources
Mode
Transmit mode
Receive mode
State
Normal
Error
Normal
Error
Flag
TEND
FER/ERS
RDRF
PER,
ORER
Mask Bit
TIE
RIE
RIE
RIE
Interrupt Source
TXI
ERI
RXI
ERI
15.5 Usage Note
When the SCI is used as a smart card interface, be sure that all criteria in sections 15.4.1 and
15.4.2 are applied.
Receive Data Timing and Receive Margin in Asynchronous Mode:
In asynchronous mode, the SCI runs on a basic clock with a frequency of 372 times the transfer
rate. During reception, the SCI samples the falling of the start bit using the base clock to achieve
internal synchronization. Receive data is latched internally on the rising edge of the 186th basic
clock cycle (figure 15.8).
Rev. 5.00 May 29, 2006 page 437 of 698
REJ09B0146-0500