H8S-2350 RENESAS [Renesas Technology Corp], H8S-2350 Datasheet - Page 663

• Manufacturer Part Number: H8S-2350
• Description: 16-Bit Single-Chip Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 14 Smart Card Interface
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 14.4 shows
a flowchart for transmitting, and figure 14.5 shows the relation between a transmit operation and
the internal registers.
[1] Perform Smart Card interface mode initialization as described above in Initialization.
[2] Check that the ERS error flag in SSR is cleared to 0.
[3] Repeat steps [2] and [3] until it can be confirmed that the TEND flag in SSR is set to 1.
[4] Write the transmit data to TDR, clear the TDRE flag to 0, and perform the transmit operation.
The TEND flag is cleared to 0.
[5] When transmitting data continuously, go back to step [2].
[6] To end transmission, clear the TE bit to 0.
With the above processing, interrupt servicing or data transfer by the DMAC or DTC 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 transfer error interrupt (ERI) request will be generated.
The timing for setting the TEND flag depends on the value of the GM bit in SMR. The TEND flag
set timing is shown in figure 14.6.
If the DMAC or DTC is activated by a TXI request, the number of bytes set in the DMAC or DTC
can be transmitted automatically, including automatic retransmission.
For details, see Interrupt Operations and Data Transfer Operation by DMAC or DTC below.
Rev. 3.00 Sep 15, 2006 page 629 of 988
REJ09B0330-0300