SH7065 Datasheet, PDF (603/941 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 the transmit FIFO data register (SCFTDR), the SCI transfers the data
from SCFTDR to the transmit shift register (SCTSR), and starts transmitting. Check that the
TDFE flag is set to 1 in the serial status 1 register (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 the FIFO
control register (SCFCR) during transmission, the TDFE flag is set. If the TIE bit setting in the
serial control register (SCSCR) is 1 at this time, a transmit-FIFO-data-empty interrupt (TXI) is
requested.
When clock output mode has been set, the SCI outputs 8 serial clock pulses for one unit of
data.
When use of an external clock has been specified, data is output in synchronization with the
input clock.
The serial transmit data is sent from the TxD pin starting with the LSB (bit 0) or MSB (bit 7)
according to the setting of the TLM bit in the serial status 2 register (SC2SSR).
3. The SCI checks for transmit data in SCFTDR at the timing for sending the last bit. If there is
data in SCFTDR, it is transferred to SCTSR 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 the serial status 1
register (SC1SSR), the last bit is sent, and then the transmit data pin (TxD) holds its state.
If the transmit-end interrupt enable bit (TEIE) setting in SCSCR is 1 at this time, a transmit-
end interrupt (TEI) is requested.
4. After completion of serial transmission, the SCK pin is fixed high.
Figure 14.19 shows an example of SCI operation in transmission.
Rev. 5.00 Sep 11, 2006 page 581 of 916
REJ09B0332-0500