SH7708 datasheet(432/633 Pages) RENESAS

432 / 633 page

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Serial Data Transmission: The handling procedures in the smart card mode differ from ordinary

SCI processing because data is retransmitted when an error signal is sampled during a data

transmission. This results in the transmission processing flowchart shown in figure 14.6.

1. Initialize the smart card interface mode as described in initialization above.

2. Check that the FER/ERS bit in SCSSR is cleared to 0.

3. Repeat steps 2 and 3 until the TEND flag in SCSSR is set to 1.

4. Write the transmit data into SCTDR, clear the TDRE flag to 0 and start transmitting. The

TEND flag will be cleared to 0.

5. To transmit more data, return to step 2.

6. To end transmission, clear the TE bit to 0.

This processing can be interrupted. When the TIE bit is set to 1 and interrupt requests are enabled,

a transmit-data-empty interrupt (TXI) will be requested when the TEND flag is set to 1 at the end

of the transmission. When the RIE bit is set to 1 and interrupt requests are enabled, a

communication error interrupt (ERI) will be requested when the ERS flag is set to 1 when an error

occurs in transmission. See Interrupt Operation below for more information.

SH7708 Datasheet(PDF) 432 Page - Renesas Technology Corp