Intel Embedded Microcontroller, 8XC251SA, 8XC251SP, 8XC251SQ, 8XC251SB manual Uart

8XC251SA, SB, SP, SQ USER’S MANUAL

set	The term set refers to the value of a bit or the act of
	giving it a value. If a bit is set, its value is “1”; setting
	a bit gives it a “1” value.
SFR	Special-function register.
sign extension	A method for converting data to a larger format by
	filling the extra bit positions with the value of the
	sign. This conversion preserves the positive or
	negative value of signed integers.
sink current	Current flowing into a device to ground. Always a
	positive value.
source-code compatibility	The ability of an MCS 251 microcontroller to execute
	recompiled source code written for an MCS 51 micro-
	controller.
source current	Current flowing out of a device from VCC. Always a
	negative value.
source mode	An operating mode that is selected by a configuration
	bit. In source mode, an MCS 251 microcontroller can
	execute recompiled source code written for an MCS
	51 microcontroller. In source mode, the MCS 251
	microcontroller cannot execute unmodified binary
	code written for an MCS 51 microcontroller. See
	binary mode.
SP	Stack pointer.
SPX	Extended stack pointer.
state time (or state)	The basic time unit of the device; the combined
	period of the two internal timing signals, PH1 and
	PH2. (The internal clock generator produces PH1 and
	PH2 by halving the frequency of the signal on
	XTAL1.) With a 16-MHz crystal, one state time
	equals 125 ns. Because the device can operate at
	many frequencies, this manual defines time require-
	ments in terms of state times rather than in specific
	units of time.
UART	Universal asynchronous receiver and transmitter. A
	part of the serial I/O port.
WDT	Watchdog timer, an internal timer that resets the
	device if the software fails to operate properly.
Glossary-6