Intel 8XC196MC, 8XC196MD manual Programming the Serial Port, Configuring the Serial Port Pins, 00H

8XC196MC, MD, MH USER’S MANUAL

7.4PROGRAMMING THE SERIAL PORT

To use the SIO port, you must configure the port pins to serve as special-function signals and set up the SIO channels.

7.4.1Configuring the Serial Port Pins

Before you can use the serial port, you must configure the associated port pins to serve as special- function signals. Table 7-1 on page 7-2 lists the pins associated with the serial port. Table 7-2 on page 7-2 lists the port configuration registers, and Chapter 6, “I/O Ports,” explains how to con- figure the pins.

7.4.2Programming the Control Register

The SPx_CON register (Figure 7-6) selects the communication mode and enables or disables the receiver, parity checking, and nine-bit data transmissions. Selecting a new mode resets the serial I/O port and aborts any transmission or reception in progress on the channel.

SPx_CON	Address:	1F83H, 1F8BH
x = 0–1 (8XC196MH)	Reset State:	00H

The serial port control (SPx_CON) register selects the communications mode and enables or disables the receiver, parity checking, and nine-bit data transmission.

	7										0
8XC196MH		M2		DIR	PAR	TB8		REN	PEN	M1	M0
Bit		Bit					Function
Number	Mnemonic
7	M2		See description for bits 0 and 1.
6	DIR		Synchronous Clock Direction
			This bit determines the direction of the clock during synchronous mode.
			0	= output
			1	= input
5	PAR		Parity Selection Bit
			This bit selects even or odd parity.
			0	= even parity
			1	= odd parity
4	TB8		Transmit Ninth Data Bit
			This is the ninth data bit that will be transmitted in mode 2 or 3. This bit is
			cleared after each transmission, so it must be set before SBUFx_TX is
			written. When parity is enabled (SPx_CON.2 = 1), this bit takes on the
			even parity value.

Figure 7-6. Serial Port Control (SPx_CON) Register

7-10