32186 datasheet(596/1032 Pages) RENESAS

596 / 1032 page

SERIAL INTERFACE

12-48

32185/32186 Group Hardware Manual

Rev.1.10 REJ09B0235-0110 May 15, 07

12.6.3 Initializing UART Transmission

To transmit data in UART mode, initialize the serial interface following the procedure described below.

(1) Setting SIO Special Mode Register

• Select the clock divider count source.

• Set the data bit transfer order.

• 3-points sampling control.

(2) Setting SIO Transmit/Receive Mode Register

• Set the register to UART mode.

• Set parity (when enabled, select odd/even).

• Set the stop bit length.

• Set the character length (Note 1).

Note 1: During UART mode, settings of the internal/external clock select bit have no effect (only the

internal clock is useful).

(3) Setting SIO Transmit Control Register

Select the clock divider’s divide-by ratio.

(4) Setting SIO Baud Rate Register

Set a baud rate generator value. (See Section 12.6.1, “Setting the UART Baud Rate.”)

(5) Setting SIO interrupt related registers

• Select the source of transmit interrupt request (transmit buffer empty or transmission finished)

(SIO Interrupt Request Source Select Register).

• Enable or disable SIO transmit interrupt requests (SIO Interrupt Request Mask Register).

(6) Setting Interrupt Controller (SIO Transmit Interrupt Control Register)

To use transmit interrupts, set their priority levels.

(7) Setting DMAC

To issue DMA transfer requests to the internal DMAC when the transmit buffer is empty, set up the

DMAC. (See Chapter 9, “DMAC.”)

(8) Selecting pin functions

Because the serial interface related pins serve dual purposes, set the pin functions for use as SIO

pins or input/output ports. (See Chapter 8, “Input/Output Ports and Pin Functions.”)

12.6 Transmit Operation in UART Mode

32186 Datasheet(PDF) 596 Page - Renesas Technology Corp