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Clock-Synchronous Serial I/O

M30240 Group

Rev.1.00 Sep 24, 2003 Page 178 of 360

The clock-synchronous serial I/O has three types of CTS/RTS functions to choose from:

(b) Function for choosing polarity

This function switches the polarity of the transfer clock. The following operations are available:

Choose either of the following functions to transit data from bit 0 or bit 7.

(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

the receive buffer register into a dummy manner.

(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

• CTS

/RTS functions disabled

CTS/RTS pin is a programmable I/O port.

• CTS function only enabled

CTS/RTS pin performs the CTS function.

• RTS function only enabled

CTS/RTS pin performs the RTS function.

• 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.

• LSB first

Data is transmitted from bit 0.

• MSB first

Data is transmitted from bit 7.

• Normal mode

Writing dummy data to the transmit buffer register

makes the reception enabled status ready.

• Continuous reception mode

Reading the reception buffer register makes the

reception-enabled status ready.

Renesas M16C Series User Manual

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