Datasheet

Table Of Contents
Section 17 Serial Communications Interface 3 (SCI3, IrDA)
Rev. 2.00 Jul. 04, 2007 Page 387 of 692
REJ09B0309-0200
1 frame
Start
bit
Start
bit
Receive
data
Receive
data
Parity
bit
Stop
bit
Parity
bit
Stop
bit
Mark state
(idle state)
1 frame
01 D0 D1 D7 0/1 1 0 10 D0 D1 D7 0/1
Serial
data
RDRF
FER
LSI
operation
User
processing
RDRF
cleared to 0
RDR data read
Framing error
processing
RXI3 interrupt
request
generated
0 stop bit
detected
ERI3 request in
response to
framing error
Figure 17.7 Example SCI3 Operation in Reception in Asynchronous Mode
(8-Bit Data, Parity, One Stop Bit)
Table 17.12 shows the states of the SSR status flags and receive data handling when a receive
error is detected. If a receive error is detected, the RDRF flag retains its state before receiving
data. Reception cannot be resumed while a receive error flag is set to 1. Accordingly, clear the
OER, FER, PER, and RDRF bits to 0 before resuming reception. Figure 17.8 shows a sample
flowchart for serial data reception.
Table 17.12 SSR Status Flags and Receive Data Handling
SSR Status Flag
RDRF* OER FER PER Receive Data Receive Error Type
1 1 0 0 Lost Overrun error
0 0 1 0 Transferred to RDR Framing error
0 0 0 1 Transferred to RDR Parity error
1 1 1 0 Lost Overrun error + framing error
1 1 0 1 Lost Overrun error + parity error
0 0 1 1 Transferred to RDR Framing error + parity error
1 1 1 1 Lost Overrun error + framing error +
parity error
Note: * The RDRF flag retains the state it had before data reception. However, note that if RDR
is read after an overrun error has occurred in a frame because reading of the receive
data in the previous frame was delayed, the RDRF flag will be cleared to 0.