h8s-2635 Renesas Electronics Corporation., h8s-2635 Datasheet - Page 583

• Manufacturer Part Number: h8s-2635
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 14 Smart Card Interface
Serial Data Transmission (Except Block Transfer Mode): 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 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 DTC * is activated by a TXI request, the number of bytes set in the DTC * can be transmitted
automatically, including automatic retransmission.
For details, see Interrupt Operation and Data Transfer Operation by DTC below.
Notes: For block transfer mode, see section 13.3.2, Operation in Asynchronous Mode.
* The DTC is not implemented in the H8S/2635 and H8S/2634.
Rev. 6.00 Feb 22, 2005 page 523 of 1484
REJ09B0103-0600