SH7708 Datasheet, PDF (439/633 Pages) Renesas Technology Corp – SuperH™ RISC engine

Retransmission by the SCI in Transmit Mode: Figure 14.10 shows the retransmission operation
in the SCI transmit mode.
1. After transmission of one frame is completed, the FER/ERS bit in SCSSR is set to 1 when a
error signal is returned from the receiving side. If the RIE bit in SCSCR is enabled at this time,
an ERI interrupt is requested. Be sure to clear the FER/ERS bit before the next parity bit is
sampled.
2. The TEND bit in SCSSR is not set in the frame that received the error signal that indicated the
error.
3. The FER/ERS bit in SCSR is not set when no error signal is returned from the receiving side.
4. When no error signal is returned from the receiving side, the TEND bit in SCSSR is set to 1
when the transmission of the frame that includes the retransmission is considered completed. If
the TIE bit in SCSCR is enabled at this time, a TXI interrupt will be requested.
nth transfer frame
Ds D0 D1 D2 D3 D4 D5 D6 D7 Dp DE
Retransmitted frame
Transfer frame n + 1
(DE)
Ds D0 D1 D2 D3 D4 D5 D6 D7 Dp
Ds D0 D1 D2 D3 D4
TDRE
Transfer from TDR to TRS
TEND
Transfer from TDR to TRS
Transfer from
TDR to TRS
2
FER/ERS
1
4
3
Figure 14.10 Retransmission in SCI Transmit Mode
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