Glossary - The HCS12/9S12: An Introduction to Software and Hardware Interfacing - page 837

Simplex link A line that is dedicated either for transmission or reception, but not both.
Simulator A program that allows the user to execute microcontroller programs without
having the hardware.
Single-chip mode The operation mode in which the HCS12 functions without external
address and data buses.
Source code A program written in either an assembly language or a high-level language; also
called a source program.
Source-level debugger A program that allows the user to find problems in user code at the
high-level language (such as C) or assembly-language level.
Space A term used to indicate a binary 0.
Special test mode The HCS12 operation mode used primarily during Freescale's internal
production testing.
Stack A last-in-first-out data structure whose elements can be accessed only from one end.
A stack structure has a top and a bottom. A new item can be added only to the top, and the
stack elements can be removed only from the top.
Stack frame A region in the stack that holds incoming parameters, the subroutine return
address, local variables, saved registers, and so on.
Standard timer module The timer module implemented in some HCS12 members. This
module consists of a 16-bit main timer, 8 channels of output-compare/input-capture
function, and one 16-bit pulse accumulator.
Start condition A signal condition that the I 2 C protocol requires all data transmission to start
with. A start condition is a condition that the SDA signal goes from high to low when the
SCL signal is high.
Static memories Memory devices that do not require periodic refreshing in order to retain the
stored information as long as power is applied.
Status register A register located in the CPU that keeps track of the status of instruction
execution by noting the presence of carries, zeros, negatives, overflows, and so on.
Stepper motor A digital motor that rotates certain degrees clockwise or counterclockwise
whenever a certain sequence of values is applied to the motor.
Stop condition In the I 2 C protocol, all data transfer must be terminated by a stop
condition. A stop condition is generated by bringing the SDA line from low to high
when the SCL signal is high.
String A sequence of characters terminated by a NULL character or other special character.
Subroutine A sequence of instructions that can be called from various places in the program
and will return to the caller after its execution. When a subroutine is called, the return
address will be saved on the stack.
Subroutine call The process of invoking the subroutine to perform the desired operations.
The HCS12 has BSR, JSR, and CALL instructions for making subroutine calls.
Successive approximation method A method for performing an A/D conversion that works
from the most significant bit toward the least significant bit. For every bit, the algorithm
guesses the bit to be 1, converts the resultant value into the analog voltage, and then
compares it with the input voltage. If the converted voltage is smaller than the input
voltage, the guess is right. Otherwise, the guess is wrong and the bit is cleared to 0.
Switch statement A multiway decision based on the value of a control expression.
Sync_seg In the CAN format, the sync_seg segment is the segment within a bit time used to
synchronize all CAN nodes.