HD6412332 RENESAS [Renesas Technology Corp], HD6412332 Datasheet - Page 721

• Manufacturer Part Number: HD6412332
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2300 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 15 Smart Card Interface
Data Transfer Operation by DMAC or DTC: In smart card mode, as with the normal SCI,
transfer can be carried out using the DMAC or DTC. In a transmit operation, the TDRE flag is
also set to 1 at the same time as the TEND flag in SSR, and a TXI interrupt is generated. If the
TXI request is designated beforehand as a DMAC or DTC activation source, the DMAC or DTC
will be activated by the TXI request, and transfer of the transmit data will be carried out. The
TDRE and TEND flags are automatically cleared to 0 when data transfer is performed by the
DMAC or DTC. In the event of an error, the SCI retransmits the same data automatically. The
TEND flag remains cleared to 0 during this time, and the DMAC is not activated. Thus, the
number of bytes specified by the SCI and DMAC are transmitted automatically even in
retransmission following an error. However, the ERS flag is not cleared automatically when an
error occurs, and so 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 performing transfer using the DMAC or DTC, it is essential to set and enable the DMAC or
DTC before carrying out SCI setting. For details of the DMAC and DTC setting procedures, see
section 7, DMA Controller, and section 8, Data Transfer Controller.
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 DMAC or DTC activation source, the DMAC
or DTC will be activated by the RXI request, and transfer of the receive data will be carried out.
The RDRF flag is cleared to 0 automatically when data transfer is performed by the DMAC or
DTC. If an error occurs, an error flag is set but the RDRF flag is not. Consequently, the DMAC or
DTC is not activated, but instead, an ERI interrupt request is sent to the CPU. Therefore, the error
flag should be cleared.
Note: For details of operation in block transfer mode, see section 14.4, SCI Interrupts.
Rev.4.00 Sep. 07, 2007 Page 691 of 1210
REJ09B0245-0400