HD6412373R RENESAS [Renesas Technology Corp], HD6412373R Datasheet - Page 833

• Manufacturer Part Number: HD6412373R
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2300 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 15 Serial Communication Interface (SCI, IrDA)
When performing transfer using the DTC or DMAC, it is essential to set and enable the DTC or
DMAC before carrying out SCI setting. For details on the DTC or DMAC setting procedures,
refer to section 9, Data Transfer Controller (DTC) or section 7, DMA Controller (DMAC).
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 or DMAC activation source, the DTC or
DMAC 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 DTC or
DMAC. If an error occurs, an error flag is set but the RDRF flag is not. Consequently, the DTC or
DMAC is not activated, but instead, an ERI interrupt request is sent to the CPU. Therefore, the
error flag should be cleared.
15.10
Usage Notes
15.10.1 Module Stop Mode Setting
SCI operation can be disabled or enabled using the module stop control register. The initial setting
is for SCI operation to be halted. Register access is enabled by clearing module stop mode. For
details, refer to section 24, Power-Down Modes.
15.10.2 Break Detection and Processing
When framing error detection is performed, a break can be detected by reading the RxD pin value
directly. In a break, the input from the RxD pin becomes all 0s, and so the FER flag is set, and the
PER flag may also be set. Note that, since the SCI continues the receive operation after receiving a
break, even if the FER flag is cleared to 0, it will be set to 1 again.
15.10.3 Mark State and Break Sending
When TE is 0, the TxD pin is used as an I/O port whose direction (input or output) and level are
determined by DR and DDR. This can be used to set the TxD pin to mark state or send a break
during serial data transmission. To maintain the communication line at mark state until TE is set to
1, set both DDR and DR to 1. Since TE is cleared to 0 at this point, the TxD pin becomes an I/O
port, and 1 is output from the TxD pin. To send a break during serial transmission, first set DDR
to 1 and clear DR to 0, and then clear TE to 0. When TE is cleared to 0, the transmitter is
initialized regardless of the current transmission state, the TxD pin becomes an I/O port, and 0 is
output from the TxD pin.
Rev.7.00 Mar. 18, 2009 page 765 of 1136
REJ09B0109-0700