Intel 8XC196MD, 8XC196MH, 8XC196MC manual Serial I/O Port Signals and Registers, Serial Port Signals

8XC196MC, MD, MH USER’S MANUAL

An independent, 15-bit baud-rate generator controls the baud rate of the serial port. Either XTAL1 or BCLKx can provide the clock signal for modes 0–3. In mode 4, the internal shift clock is output on SCLKx# or an external shift clock is input on SCLKx# (in which case the baud-rate generator is not used). The baud-rate register (SPx_BAUD) selects the clock source and the baud rate. The serial port control register (SPx_CON) register controls whether SCLKx# outputs the internal shift clock or inputs an external shift clock.

7.2SERIAL I/O PORT SIGNALS AND REGISTERS

Table 7-1 describes the SIO signals and Table 7-2 describes the control and status registers.

Table 7-1. Serial Port Signals

		Serial
Port	Serial Port	Port	Description
Pin	Signal	Signal
		Type
P1.0	TXD0	O	Transmit Serial Data.
P1.2	TXD1		In modes 1, 2, 3, and 4, TXDx transmits serial port output data. In
			mode 0, it is the serial clock output.
P1.1	RXD0	I/O	Receive Serial Data.
P1.3	RXD1		In modes 1, 2, 3, and 4, RXDx receives serial port input data. In mode
			0, it functions as an input or an open-drain output for data.
P2.1	SCLK0#/BCLK0	I/O	Baud Clock.
P2.7	SCLK1#/BCLK1		BCLKx can provide an external clock source for the baud-rate
			generator input.
			Shift Clock. In mode 4 only, SCLKx# are bidirectional shift clock
			signals that synchronize the serial data transfer. The DIR bit in the
			SP_CON register controls the direction of SCLKx#:
			DIR = 0 causes SCLKx# to output the internal shift clock.
			DIR = 1 allows an external shift clock to be input on SCLKx#.

Table 7-2. Serial Port Control and Status Registers

Mnemonic	Address	Description
INT_MASK1	0013H	Interrupt Mask 1
		Setting the TIx bit enables the transmit interrupt; clearing the bit
		disables (masks) the interrupt.
		Setting the RIx bit enables the receive interrupt; clearing the bit
		disables (masks) the interrupt.
		Setting the SPE bit enables the serial port receive error interrupt.

7-2