SH7708 Datasheet, PDF (428/625 Pages) Renesas Technology Corp – SuperH™ RISC engine

14.4.2 Retransmission (Receive and Transmit Modes)
Retransmission by the SCI in Receive Mode: Figure 14.9 shows the retransmission
operation in the SCI receive mode.
1. When the received parity bit is checked and an error is found, the PER bit in SCSSR is
automatically set to 1. If the RIE bit in SCSCR is enabled at this time, an ERI interrupt is
requested. Be sure to clear the PER bit before the next parity bit is sampled.
2. The RDRF bit in SCSSR is not set in the frame that caused the error.
3. When the received parity bit is checked and no error is found, the PER bit in SCSSR is
not set.
4. When the received parity bit is checked and no error is found, reception is considered to
have been completed normally and the RDRF bit in SCSSR is automatically set to 1. If
the RIE bit in SCSCR is enabled at this time, an RXI interrupt is requested.
5. When a normal frame is received, the pin maintains a three-state status when it transmits
the error signal.
nth transfer frame
Retransmitted frame
Transfer frame n + 1
Ds D0 D1 D2 D3 D4 D5 D6 D7 Dp DE
RDRF
2
PER
1
(DE)
Ds D0 D1 D2 D3 D4 D5 D6 D7 Dp
Ds D0 D1 D2 D3 D4
5
4
3
Figure 14.9 Retransmission in SCI Receive Mode
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