Glossary - The HCS12/9S12: An Introduction to Software and Hardware Interfacing - page 831

CRC error (Cyclic redundancy check error) In data communications, the CRC sequence
consists of the result of the CRC calculation by the transmitter. The receiver calculates the
CRC in the same way as the transmitter. A CRC error is detected if the calculated result is
not the same as that received in the CRC sequence.
Cross assembler An assembler that runs on one computer but generates machine instructions
that will be executed by another computer that has a different instruction set.
Cross compiler A compiler that runs on one computer but generates machine instructions
that will be executed by another computer that has a different instruction set.
D/A converter A circuit that can convert a digital value into an analog voltage.
Data hold time The length of time over which the data must remain stable after the edge of
the control signal that latches the data.
Datapath The part of the processor that consists of a register file and the ALU.
Data setup time The amount of time over which the data must become valid before the edge
of the control signal that latches the data.
D-Bug12 monitor A monitor program designed for the HCS12 microcontroller.
Data communication equipment (DCE)

Equipment such as a modem, concentrator, router,

and so on.
Demo board A single-board computer that contains the target microcontroller as the CPU
and a monitor to help the user perform embedded product development.
Direct mode An addressing mode that uses an 8-bit value to represent the address of a
memory location.
Dominant level A voltage level in a CAN bus that will prevail when a voltage level at this
state and a different level ( recessive level ) are applied to the CAN bus at the same time.
Data terminal equipment (DTE) A computer or terminal.
Dynamic memories Memory devices that require periodic refreshing of the stored information,
even when power is on.
EIA Electronic Industry Association.
Electrically erasable programmable read-only memory (EEPROM) A type of read-only
memory that can be erased and reprogrammed using electric signals. EEPROM allows each
individual location inside the chip to be erased and reprogrammed.
Embedded system A product that uses a microcontroller as the controller to provide the
features. End users are interested in these features rather than the power of the micro-
controller. A cell phone, a charge card, a weather station, and a home security system
are examples of embedded systems.
Erasable programmable read-only memory (EPROM) A type of read-only memory that can be
erased by subjecting it to strong ultraviolet light. It can be reprogrammed using an EPROM
programmer. A quartz window on top of the EPROM chip allows light to be shone directly
on the silicon chip inside.
Error active A CAN node that has both the transmit error count and receive error count lower

than 127.
Error passive A CAN node that has either the transmit error count or the receive error count
between 128 and 256.
Exception Software interrupts such as an illegal opcode, an overflow, division by zero, or an
underflow.
Expanded mode An operation mode in which the HCS12 can access external memory components
by sending out address signals. A 1-MB memory space is available in this mode.