Datasheet

Table Of Contents
Section 13 Serial Communication Interface
REJ09B0140-0900 Rev. 9.00 Page 455 of 846
Sep 16, 2010
H8S/2215 Group
13.7.8 Serial Data Reception (Except for Block Transfer Mode)
Data reception in Smart Card interface mode uses the same operation procedure as for normal
serial communication interface mode. Figure 13.33 illustrates the retransfer operation when the
SCI is in receive mode.
1. If an error is found when the received parity bit is checked, the PER bit in SSR is
automatically set to 1. If the RIE bit in SCR is set at this time, an ERI interrupt request is
generated. The PER bit in SSR should be kept cleared to 0 until the next parity bit is sampled.
2. The RDRF bit in SSR is not set for a frame in which an error has occurred.
3. If no error is found when the received parity bit is checked, the PER bit in SSR is not set to 1,
the receive operation is judged to have been completed normally, and the RDRF flag in SSR is
automatically set to 1. If the RIE bit in SCR is enabled at this time, an RXI interrupt request is
generated.
Figure 13.34 shows a flowchart for reception. A sequence of receive operations can be performed
automatically by specifying the DTC
*
or the DMAC to be activated using an RXI interrupt
source. In a receive operation, an RXI interrupt request is generated when the RDRF flag in SSR
is set to 1. If the RXI request is designated beforehand as a DTC
*
or the DMAC activation source,
the DTC
*
or the DMAC will be activated by the RXI request, and the receive data will be
transferred. The RDRF flag is cleared to 0 automatically when data is transferred by the DTC
*
or
the DMAC. If an error occurs in receive mode and the ORER or PER flag is set to 1, a transfer
error interrupt (ERI) request will be generated. Hence, so the error flag must be cleared to 0. In the
event of an error, the DTC
*
or the DMAC is not activated and receive data is skipped. Therefore,
receive data is transferred for only the specified number of bytes in the event of an error. Even
when a parity error occurs in receive mode and the PER flag is set to 1, the data that has been
received is transferred to RDR and can be read from there.
Notes: For details on receive operations in block transfer mode, refer to section 13.4, Operation in
Asynchronous Mode.
* The Flags are automatically cleared by the DTC when the DTC's DISEL bit is cleared
to 0 and the transfer counter value is not 0.