3069RF-ZTAT Datasheet, PDF (531/1003 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER

Simultaneous Multiple Receive Errors: Table 13.13 shows the state of the SSR status flags
when multiple receive errors occur simultaneously. When an overrun error occurs the RSR
contents are not transferred to RDR, so receive data is lost.
Table 13.13 SSR Status Flags and Transfer of Receive Data
RDRF
1
0
0
1
1
0
1
SSR Status Flags
ORER
FER
1
0
0
1
0
0
1
1
1
0
0
1
1
1
PER
0
0
1
0
1
1
1
Notes: : Receive data is transferred from RSR to RDR.
× : Receive data is not transferred from RSR to RDR.
Receive Data
Transfer
RSR → RDR
×
×
×
×
Receive Errors
Overrun error
Framing error
Parity error
Overrun error +
framing error
Overrun error +
parity error
Framing error +
parity error
Overrun error +
framing error +
parity error
Break Detection and Processing: Break signals can be detected by reading the RxD pin directly
when a framing error (FER) is detected. In the break state the input from the RxD pin consists of
all 0s, so the FER flag is set and the parity error flag (PER) may also be set. In the break state the
SCI receiver continues to operate, so if the FER flag is cleared to 0 it will be set to 1 again.
Sending a Break Signal: The input/output condition and level of the TxD pin are determined by
DR and DDR bits. This feature can be used to send a break signal.
After the serial transmitter is initialized, the DR value substitutes for the mark state until the TE
bit is set to 1 (the TxD pin function is not selected until the TE bit is set to 1). The DDR and DR
bits should therefore be set to 1 beforehand.
To send a break signal during serial transmission, clear the DR bit to 0 , then clear the TE bit to 0.
When the TE bit is cleared to 0 the transmitter is initialized, regardless of its current state, so the
TxD pin becomes an input/output outputting the value 0.
Rev. 5.0, 09/04, page 509 of 978