SH7261 Datasheet, PDF (759/1348 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7260 Series

Section 16 Serial Communication Interface with FIFO (SCIF)
16.6.3 Restriction on DMAC Usage
1. When the DMAC writes data to SCFTDR with a TXI interrupt request, the state of the TEND
flag becomes undefined. Therefore, the TEND flag should not be used as the transfer end flag
in such a case.
2. When one channel is used in full duplex communication with the DMAC used for transmission
and the CPU used for reception, if the receive data are read from the receive FIFO data register
(SCFRDR) after the RDF or DR flag in the serial status register (SCFSR) has been set, the
RDF or DR flag may be cleared.
3. When one channel is used in full duplex communication with the DMAC used for reception
and the CPU used for transmission, if the transmit data is written to the transmit FIFO data
register (SCFTDR) after the TDFE or TEND flag in the serial status register (SCFSR) has been
set, the TDFE or TEND flags may be cleared.
16.6.4 Break Detection and Processing
Break signals can be detected by reading the RxD pin directly when a framing error (FER) is
detected. In the break state the input from the RxD pin consists of all 0s, so the FER flag is set and
the parity error flag (PER) may also be set.
Note that, although transfer of receive data to SCFRDR is halted in the break state, the SCIF
receiver continues to operate.
16.6.5 Sending a Break Signal
The I/O condition and level of the TxD pin are determined by the SPB2IO and SPB2DT bits in the
serial port register (SCSPTR). This feature can be used to send a break signal.
Until TE bit is set to 1 (enabling transmission) after initializing, the TxD pin does not work.
During the period, mark status is performed by the SPB2DT bit. Therefore, the SPB2IO and
SPB2DT bits should be set to 1 (high level output).
To send a break signal during serial transmission, clear the SPB2DT bit to 0 (designating low
level), then clear the TE bit to 0 (halting transmission). When the TE bit is cleared to 0, the
transmitter is initialized regardless of the current transmission state, and 0 is output from the TxD
pin.
Rev. 2.00 Sep. 07, 2007 Page 727 of 1312
REJ09B0320-0200