Serial Data Transmission (Except In Block Transfer Mode) - Renesas RX100 Series User Manual

RX13T Group
23.6.6

Serial Data Transmission (Except in Block Transfer Mode)

Serial data transmission in smart card interface mode (except in block transfer mode), in that an error signal is sampled
and data can be retransmitted, is different from that in non-smart card interface mode. Figure 23.39 shows the data
retransmit operation during transmission.
Ds D0 D1 D2
TXI interrupt signal
SSR.FER flag/
SSR.ERS flag
Figure 23.39 Data Retransmit Operation in SCI Transmit Mode
(1) When an error signal from the receiver end is sampled after one-frame data has been transmitted, the ERS flag in the
SSR register is set to 1. If the RIE bit in the SCR register is 1 at this time, an ERI interrupt request is generated.
Clear the ERS flag to 0 before the next parity bit is sampled.
(2) For a frame in which an error signal is received, the TEND flag in the SSR register is not set. Data is retransferred
from the TDR register to the TSR register allowing automatic data retransmission.
(3) If no error signal is returned from the receiver, the ERS flag is not set to 1.
(4) In this case, the SCI judges that transmission of one-frame data (including retransmission) has been completed, and
the TEND flag is set. If the TIE bit in the SCR register is 1 at this time, a TXI interrupt request is generated. Writing
transmit data to the TDR register starts transmission of the next data.
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
nth transmitted frame
D3 D4 D5 D6 D7 Dp DE
(2)
(1)
23. Serial Communications Interface (SCIg, SCIh)
Retransmitted frame
Ds D0 D1 D2 D3 D4 D5 D6 D7 Dp
(n + 1)-th
transmitted frame
(DE)
Ds D0 D1 D2 D3 D4
(4)
(3)
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