Table of Contents
Advertisement
Retransmission: Retransmission is described below for the separate cases of transmit mode and
receive mode.
www.DataSheet4U.com
Retransmission when SCI is in Receive Mode (See Figure 14-11):
(1) The SCI checks the received parity bit. If it detects an error, it automatically sets the PER flag
to 1. If the RIE bit in SCR is set to the enable state, an ERI interrupt is requested. The PER
flag should be cleared to 0 in SSR before the next parity bit sampling timing.
(2) The RDRF bit in SSR is not set to 1 for the error frame.
(3) If an error is not detected when the parity bit is checked, the PER flag is not set in SSR.
(4) If an error is not detected when the parity bit is checked, receiving operations are assumed to
have ended normally, and the RDRF bit is automatically set to 1 in SSR. If the RIE bit in SCR
is set to the enable state, an RXI interrupt is requested. If RXI is enabled as a DMA transfer
activation source, the RDR contents can be read automatically. When the DMAC reads the
RDR data, it automatically clears RDRF to 0.
(5) When a normal frame is received, at the error signal transmit timing, the data pin is held in
the high-impedance state.
Ds D0 D1 D2 D3 D4 D5 D6 D7 Dp
RDRF
PER
Frame n
DE
Ds D0 D1 D2 D3 D4 D5 D6 D7 Dp
(2)
(1)
Figure 14-11 Retransmission in SCI Receive Mode
Retransmitted frame
521
Frame n + 1
(DE)
Ds
D0 D1 D2 D3 D4
(4)
(3)
Advertisement
Table of Contents
