M16C30P_07 Datasheet, PDF (171/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
15. Serial Interface
15.1.3.8 Initialization of Transmission/Reception
If a start condition is detected while the STAC bit = 1 (UARTi initialization enabled), the serial interface
operates as described below.
• The transmit shift register is initialized, and the content of the UiTB register is transferred to the transmit
shift register. In this way, the serial interface starts sending data synchronously with the next clock pulse
applied. However, the UARTi output value does not change state and remains the same as when a start
condition was detected until the first bit of data is output synchronously with the input clock.
• The receive shift register is initialized, and the serial interface starts receiving data synchronously with the
next clock pulse applied.
• The SWC bit is set to “1” (SCL wait output enabled). Consequently, the SCLi pin is pulled low at the
falling edge of the 9th clock pulse.
Note that when UARTi transmission/reception is started using this function, the TI does not change state. Note
also that when using this function, the selected transfer clock should be an external clock.
Rev.1.22 Mar 29, 2007 Page 155 of 291
REJ09B0179-0122