How-To Guide

Table Of Contents
R01UH0823EJ0110 Rev.1.10 Page 990 of 1852
Nov 30, 2020
RX23W Group 33. Serial Communications Interface (SCIg, SCIh)
PER Flag (Parity Error Flag)
Indicates that a parity error has occurred during reception in asynchronous mode and the reception ends abnormally.
[Setting condition]
When a parity error is detected during reception
Although receive data when the parity error occurs is transferred to the RDR register, no RXI interrupt request
occurs. Note that when the PER flag is being set to 1, the subsequent receive data is not transferred to the RDR
register.
[Clearing condition]
When 0 is written to the PER flag after reading PER = 1
When setting the PER flag to 0 to complete the interrupt handling, refer to
section 15.4.1.2, Operation of Status
Flags for Level-Detected Interrupts
.
Even when the SCR.RE bit is set to 0 (serial reception is disabled), the PER flag is not affected and retains its
previous value.
FER Flag (Framing Error Flag)
Indicates that a framing error has occurred during reception in asynchronous mode and the reception ends abnormally.
[Setting condition]
When the stop bit is 0
In 2-stop-bit mode, only the first stop bit is checked whether it is 1 but the second stop bit is not checked. Note that
although receive data when the framing error occurs is transferred to the RDR register, no RXI interrupt request
occurs. In addition, when the FER flag is being set to 1, the subsequent receive data is not transferred to the RDR
register.
[Clearing condition]
When 0 is written to the FER flag after reading FER = 1
When setting the FER flag to 0 to complete the interrupt handling, refer to
section 15.4.1.2, Operation of Status
Flags for Level-Detected Interrupts
.
Even when the SCR.RE bit is set to 0, the FER flag is not affected and retains its previous value.
ORER Flag (Overrun Error Flag)
Indicates that an overrun error has occurred during reception and the reception ends abnormally.
[Setting condition]
When the next data is received before receive data is read from the RDR register
In the RDR register, receive data prior to an overrun error occurrence is retained, but data received after the overrun
error occurrence is lost. When the ORER flag is set to 1, subsequent serial reception cannot be performed. Note that,
in clock synchronous mode, serial transmission also cannot continue.
[Clearing condition]
When 0 is written to the ORER flag after reading ORER = 1
When setting the ORER flag to 0 to complete the interrupt handling, refer to
section 15.4.1.2, Operation of
Status Flags for Level-Detected Interrupts
.
Even when the SCR.RE bit is set to 0, the ORER flag is not affected and retains its previous value.
RDRF Flag (Receive Data Full Flag)
Indicates whether the RDR register has received data.
[Setting condition]
When data has been received normally, and transferred from the RSR register to the RDR register
[Clearing condition]
When data is read from the RDR register