SH7080_09 Datasheet, PDF (889/1622 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family

Section 16 Serial Communication Interface with FIFO (SCIF)
16.4 Operation
16.4.1 Overview
For serial communication, the SCIF has an asynchronous mode in which characters are
synchronized individually, and a clock synchronous mode in which communication is
synchronized with clock pulses. The SCIF has a 16-byte FIFO buffer for both transmit and receive
operations, reducing the overhead of the CPU, and enabling continuous high-speed
communication. Moreover, it has RTS and CTS signals as modem control signals. The
transmission format is selected in the serial mode register (SCSMR) as shown in table 16.13. The
SCIF clock source is selected by the combination of the CKE1 and CKE0 bits in the serial control
register (SCSCR) as shown in table 16.14.
(1) Asynchronous Mode
• Data length is selectable: 7 or 8 bits.
• Parity bit is selectable. So is the stop bit length (1 or 2 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, receive FIFO data full,
overrun errors, receive data ready, and breaks.
• The number of stored data bytes is indicated for both the transmit and receive FIFO registers.
• An internal or external clock can be selected as the SCIF clock source.
⎯ When an internal clock is selected, the SCIF operates using the on-chip baud rate
generator.
⎯ When an external clock is selected, the external clock input must have a frequency 16 times
the bit rate. (The on-chip baud rate generator is not used.)
(2) Clock Synchronous Mode
• The transmission/reception format has a fixed 8-bit data length.
• In receiving, it is possible to detect overrun errors (ORER).
• An internal or external clock can be selected as the SCIF clock source.
⎯ When an internal clock is selected, the SCIF operates using the on-chip baud rate
generator, and outputs a serial clock signal to external devices.
⎯ When an external clock is selected, the SCIF operates on the input serial clock. The on-
chip baud rate generator is not used.
Rev. 4.00 Dec. 15, 2009 Page 829 of 1558
REJ09B0181-0400