Intel Microcontroller, 80C196NU, 8XC196NP manual Spcon, PAR TB8 PRS REN PEN, Par

SERIAL I/O (SIO) PORT

SP_CON	Address:	1FBBH
	Reset State:	00H

The serial port control (SP_CON) register selects the communications mode and enables or disables the receiver, parity checking, and nine-bit data transmission. For the 80C196NU, it also enables or disables the divide-by-two prescaler.

8XC196NP

80C196NU

7

—	—	PAR	TB8
7
—	PRS	PAR	TB8

0

REN	PEN	M1	M0
			0
REN	PEN	M1	M0

Bit	Bit	Function
Number	Mnemonic
7	—	Reserved; for compatibility with future devices, write zero to this bit.
6†	PRS	Prescale
		This bit enables the divide-by-two prescaler.
		0 =disable the prescaler
		1 =enable the prescaler
5	PAR	Parity Selection 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 SBUF_TX is
		written. When SP_CON.2 is set, this bit takes on the even parity value.
3	REN	Receive Enable
		Setting this bit enables the receiver function of the RXD pin. When this
		bit is set, a high-to-low transition on the pin starts a reception in mode 1,
		2, or 3. In mode 0, this bit must be clear for transmission to begin and
		must be set for reception to begin. Clearing this bit stops a reception in
		progress and inhibits further receptions.
2	PEN	Parity Enable
		In modes 1 and 3, setting this bit enables the parity function. This bit
		must be cleared if mode 2 is used. When this bit is set, TB8 takes the
		parity value on transmissions. With parity enabled, SP_STATUS.7
		becomes the receive parity error bit.

†This bit is reserved on the 8XC196NP. For compatibility with future devices, write zero to this bit.

Figure 8-6. Serial Port Control (SP_CON) Register

8-9