How-To Guide

Table Of Contents
R01UH0823EJ0110 Rev.1.10 Page 992 of 1852
Nov 30, 2020
RX23W Group 33. Serial Communications Interface (SCIg, SCIh)
TEND Flag (Transmit End Flag)
With no error signal from the receiving side, this bit is set to 1 when further data for transfer is ready to be transferred to
the TDR register.
[Setting conditions]
When the SCR.TE bit is 0 (serial transmission is disabled)
When the SCR.TE bit is changed from 0 to 1, the TEND flag is not affected and retains the value 1.
When a specified period has elapsed after the latest transmission of 1 byte, the ERS flag is 0, and the TDR register
is not updated
The set timing is determined by register settings as listed below.
When SMR.GM = 0 and SMR.BLK = 0, 12.5 etu after the start of transmission
When SMR.GM = 0 and SMR.BLK = 1, 11.5 etu after the start of transmission
When SMR.GM = 1 and SMR.BLK = 0, 11.0 etu after the start of transmission
When SMR.GM = 1 and SMR.BLK = 1, 11.0 etu after the start of transmission
[Clearing condition]
When transmit data are written to the TDR register while the SCR.TE bit is 1
When setting the TEND flag to 0 to complete the interrupt handling, refer to
section 15.4.1.2, Operation of
Status Flags for Level-Detected Interrupts
.
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.
ERS Flag (Error Signal Status Flag)
[Setting condition]
When a low error signal is sampled
[Clearing condition]
When 0 is written to the ERS flag after reading ERS = 1
When setting the ERS 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 ERS flag is not affected and retains its previous value.