Renesas H8S Series Hardware Manual page 413

Section 14 Serial Communication Interface (SCI)
In Smart Card interface mode, as in normal serial communication interface mode, transfer can be
carried out using the DTC. In transmit operations, the TDRE flag is also set to 1 at the same time
as the TEND flag in SSR is set, and a TXI interrupt is generated. If the TXI request is designated
beforehand as a DTC activation source, the DTC will be activated by the TXI request, and
transmit data will be transferred. The TDRE and TEND flags are automatically cleared to 0 when
data is transferred by the DTC. In the event of an error, the SCI retransmits the same data
automatically. During this period, the TEND flag remains cleared to 0 and the DTC is not
activated. Therefore, the SCI and DTC will automatically transmit the specified number of bytes
in the event of an error, including retransmission. However, the ERS flag is not cleared
automatically when an error occurs. Hence, the RIE bit should be set to 1 beforehand so that an
ERI request will be generated in the event of an error, and the ERS flag will be cleared.
When transferring using the DTC, it is essential to set and enable the DTC before carrying out SCI
setting. For details of the DTC setting procedures, refer to section 8, Data Transfer Controller
(DTC).
In receive operations, 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 activation source, the DTC 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. If an error occurs, an error flag is set but the
RDRF flag is not. Consequently, the DTC is not activated, instead, an ERI interrupt request is sent
to the CPU. Therefore, the error flag should be cleared.
Rev. 6.00 Mar 15, 2006 page 377 of 570
REJ09B0211-0600