SH7720 Datasheet, PDF (675/1524 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series

Section 18 Serial Communication Interface with FIFO (SCIF)
18.3.12 Transmit Data Stop Register (SCTDSR)
SCTDSR is an 8-bit readable/writable register that sets the number of data to be transmitted. This
register is available when the TSE bit in the FIFO control register (SCFCR) is enabled. The
transmit operation stops after all data set by this register have been transmitted. Settable values are
H'00 (1 byte) to H'FF (256 bytes). The initial value of this register is H'FF.
18.4 Operation
For serial communication, the SCIF has asynchronous mode in which characters are synchronized
individually and synchronous mode in which synchronization is achieved with clock pulses. The
SCIF has the 64-byte FIFO buffer for both transmission and reception, reduces an overhead of the
CPU, and enables continuous high-speed communication.
18.4.1 Asynchronous Mode
Operation in asynchronous mode is described below.
The transmission and reception format is selected in the serial mode register (SCSMR), as listed in
table 18.2. The clock source of SCIF is determined by the combination of CKE1 and CKE0 bits in
the serial control register (SCSCR).
• Data length is selectable from seven or eight bits.
• Parity and multiprocessor bits are selectable. So is the stop bit length (one or two bits). The
combination of the preceding selections constitutes the communication format and character
length.
• In receiving, it is possible to detect framing errors, parity errors, overrun errors, receive FIFO
data full, receive data ready, and breaks.
• The number of stored data for both the transmit and receive FIFO registers is displayed.
• Clock source: Internal clock/external clock
 Internal clock: SCIF operates using the on-chip baud rate generator
 External clock: The clock appropriate for the sampling rate should be input. For example,
when the sampling rate is 1/16, input the clock frequency 8 times the bit rate. (The internal
baud rate generator should not be used.)
Rev. 3.00 Jan. 18, 2008 Page 613 of 1458
REJ09B0033-0300