R01UH0823EJ0100 Rev.1.00 Page 1030 of 1823
Jul 31, 2019
RX23W Group 33. Serial Communications Interface (SCIg, SCIh)
Figure 33.15 Example of SCI Operation for Serial Reception in Asynchronous Mode (2)
(When RTS Function is Used) (Example with 8-Bit Data, Parity, 1 Stop Bit)
Table 33.28 lists the states of the flags in the SSR status register and receive data handling when a receive error is
detected.
If a receive error is detected, an ERI interrupt request is generated but an RXI interrupt request is not generated. Data
reception cannot be resumed while the receive error flag is 1. Accordingly, set the ORER, FER, and PER flags to 0
before resuming reception. Moreover, be sure to read the RDR (or the RDRL) during overrun error processing. When a
reception is forcibly terminated by setting the SCR.RE bit to 0 during operation, read the RDR (or the RDRL) register
because received data which has not yet been read may be left in RDR (or the RDRL).
Figure 33.16 and Figure 33.17 show samples of flowcharts for serial data reception.
Note 1. Read data not in RDR but in the RDRH and RDRL registers when 9-bit data length is selected.
Table 33.28 Flags in the SSR Status Register and Receive Data Handling
Flags in the SSR Status Register
Receive Data Receive Error TypeORER FER PER
1 0 0 Lost Overrun error
010Transferred to RDR*
1
Framing error
001Transferred to RDR*
1
Parity error
1 1 0 Lost Overrun error + framing error
1 0 1 Lost Overrun error + parity error
011Transferred to RDR*
1
Framing error + parity error
1 1 1 Lost Overrun error + framing error + parity error
RXI interrupt flag
(IRn in ICU*
1
)
SSR.FER flag
0
1 frame
D0
D7 0/1 1 0 D0 D7
0/1 0
Data Data
Parity
bit
Stop
bit
Start bit
Parity
bit
Stop
bit
Start bit
Idle state
(mark state)
ERI interrupt request
generated by framing error
RXI interrupt
request
generated
RDR data read in RXI interrupt
handling routine
RTSn# pin
Error flag is cleared
0D0
Data
Start bit
Note 1. Refer to section 15, Interrupt Controller (ICUb) for details on the corresponding interrupt vector number.
To Next Page
Loading...
Need help?
General
