RX610 Group
20. Serial Communications Interface (SCI)
R01UH0032EJ0120 Rev.1.20
Page 669 of 1006
Feb 20, 2013
20.5.7
Serial Data Reception (Except in Block Transfer Mode)
Serial data reception in smart card interface mode is similar to that in serial communications interface mode. Figure
20.28 shows the data retransfer operation in reception mode.
1. If a parity error is detected in receive data, the PER flag in SSR is set to 1. When the RIE bit in SCR is set to 1 at this
time, an ERI interrupt request is generated. Clear the PER flag to 0 before the next parity bit is sampled.
2. For a frame in which a parity error is detected, no RXI interrupt is generated.
3. When no parity error is detected, the PER flag in SSR is not set to 1.
4. In this case, data is determined to have been received successfully. When the RIE bit in SCR is set to 1, an RXI
interrupt request is generated.
Figure 20.29 shows a sample flowchart for serial data reception. All the processing steps are automatically performed
using an RXI interrupt request to activate the DTC or DMAC.
In reception, setting the RIE bit to 1 allows an RXI interrupt request to be generated. The DTC or DMAC is activated by
an RXI interrupt request if the RXI interrupt request is specified as a source of DTC or DMAC activation beforehand,
allowing transfer of receive data.
If an error occurs during reception and either the ORER or PER flag in SSR is set to 1, a receive error interrupt (ERI)
request is generated. Clear the error flag. If an error occurs, the DTC or DMAC is not activated and receive data is
skipped. Therefore, the number of bytes of receive data specified in the DTC or DMAC is transferred.
Even if a parity error occurs and the PER flag is set to 1 during reception, receive data is transferred to RDR, thus
allowing the data to be read.
Note:
For operations in block transfer mode, see section 20.3,
Operation in Asynchronous Mode
(n+1)-th transfer
frame
Retransfer frame
n-th transfer frame
Ds D0 D1 D2
D6 D7 Dp
D3 D4 D5
DE
Ds D0 D1 D2
D6 D7 Dp
D3 D4 D5
Ds D0 D1 D2 D3 D4
[1]
[2]
[4]
[3]
RXI interrupt flag
(IRn
*
of ICU)
SSR.PER flag
Note:
*
For the corresponding interrupt vector number, see section 10, Interrupt Control Unit (ICU).
Figure 20.28 Data Retransfer Operation in SCI Reception Mode