SH7065 Datasheet, PDF (594/941 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7000 Series

Section 14 Serial Communication Interface (SCI)
In serial transmission, the SCI operates as described below.
1. When data is written to SCFTDR, the SCI transfers the data to SCTSR and starts transmitting.
Check that the TDFE flag is set to 1 in SC1SSR before writing transmit data to SCFTDR. The
number of data bytes that can be written is at least {16 – (transmit trigger set number)}.
2. When data is transferred from SCFTDR to SCTSR and transmission is started, transmit
operations are performed continually until there is no transmit data left in SCFTDR. If the
number of data bytes in SCFTDR falls to or below the transmit trigger number set in SCFCR
during transmission, the TDFE flag is set to 1. If the TIE bit setting in SCSCR is 1 at this time,
a transmit-FIFO-data-empty interrupt (TXI) is requested.
The serial transmit data is sent from the TxD pin in the following order.
a. Start bit: One 0-bit is output.
b. Transmit data: 8-bit or 7-bit data is output in LSB-first or MSB-first order according to the
setting of the TLM bit in SC2SSR.
c. Multiprocessor bit: One multiprocessor bit (MPBT value) is output.
d. Stop bit(s): One or two 1-bits (stop bits) are output.
e. Mark state: 1 is output continuously until the start bit that starts the next transmission is
sent.
3. The SCI checks for transmit data in SCFTDR at the timing for sending the stop bit. If there is
data in SCFTDR, it is transferred to SCTSR, the stop bit is sent, and then serial transmission of
the next frame is started.
If there is no transmit data in SCFTDR, the TEND flag is set to 1 in SC1SSR, the stop bit is
sent, and then the line goes to the mark state in which 1 is output continuously. If the TEIE bit
setting in SCSCR is 1 at this time, a transmit-end interrupt (TEI) is requested.
Figure 14.12 shows an example of SCI operation for transmission using a multiprocessor format.
Rev. 5.00 Sep 11, 2006 page 572 of 916
REJ09B0332-0500