Renesas M16C Series User Manual page 196

M30240 Group
The clock-synchronous serial I/O has three types of CTS/RTS functions to choose from:
• CTS/RTS functions disabled
• CTS function only enabled
• RTS function only enabled
(b) Function for choosing polarity
This function switches the polarity of the transfer clock. The following operations are available:
• Data is input at the falling edge of the transfer clock, and is output at the rising edge.
• Data is input at the rising edge of the transfer clock, and is output at the falling edge.
(c) Function for choosing which bit to transmit first
Choose either of the following functions to transit data from bit 0 or bit 7.
• LSB first
• MSB first
(d) Function for choosing continuous reception mode
Continuous reception mode is a mode in which reading the receive buffer register makes the recep-
tion-enabled status ready. In this mode, there is no need to write dummy data to the transmit buffer
register so as to make the reception-enabled status ready. But at the time of starting reception, read
the receive buffer register into a dummy manner.
• Normal mode
• Continuous reception mode
(e) Function for outputting transfer clock to multiple pins
This function is to switch among pins to output the transfer clock. This function is effective only when
selecting the internal clock. Switching among pins for outputting the transfer clock allows data trans-
mission to two external Is in a time-sharing manner.
(f) Data logic select function (UART2 only)
This function is to reverse data when writing to transmit buffer register or reading from receive buffer
register.
Rev.1.00 Sep 24, 2003 Page 178 of 360
Clock-Synchronous Serial I/O
CTS/RTS pin is a programmable I/O port.
CTS/RTS pin performs the CTS function.
CTS/RTS pin performs the RTS function.
Data is transmitted from bit 0.
Data is transmitted from bit 7.
Writing dummy data to the transmit buffer register
makes the reception enabled status ready.
Reading the reception buffer register makes the
reception-enabled status ready.