Hitachi SH7750 Hardware Manual page 770

Serial Data Transmission: As data transmission in smart card mode involves error signal
sampling and retransmission processing, the processing procedure is different from that for the
normal SCI. Figure 17.8 shows a sample transmission processing flowchart.
1. Perform smart card interface mode initialization as described in Initialization above.
2. Check that the FER/ERS error flag in SCSSR1 is cleared to 0.
3. Repeat steps 2 and 3 until it can be confirmed that the TEND flag in SCSSR1 is set to 1.
4. Write the transmit data to SCTDR1, clear the TDRE flag to 0, and perform the transmit
operation. The TEND flag is cleared to 0.
5. To continue transmitting data, go back to step 2.
6. To end transmission, clear the TE bit to 0.
With the above processing, interrupt handling is possible.
If transmission ends and the TEND flag is set to 1 while the TIE bit is set to 1 and interrupt
requests are enabled, a transmit-data-empty interrupt (TXI) request will be generated. If an error
occurs in transmission and the ERS flag is set to 1 while the RIE bit is set to 1 and interrupt
requests are enabled, a transmit/receive-error interrupt (ERI) request will be generated. See
Interrupt Operation in section 17.3.6 below for details.
Rev. 6.0, 07/02, page 720 of 986