it covers some topics from embeded system. a small dictionary for Embedded computer system, help's you to know more about embedded system.

1. EMBEDDED COMPUTER
SYSTEM
SUBMITTED BY: GOVIND KAINTURA
MCA 1ST YEAR

2. EMBEDDED-SYSTEM
A SYSTEM IN WHICH THE COMPUTER (GENERALLY A
MICROCONTROLLER OR MICROPROCESSOR) IS INCLUDED AS AN
INTEGRAL PART OF THE SYSTEM. OFTEN, THE COMPUTER IS
RELATIVELY INVISIBLE TO THE USER, WITHOUT OBVIOUS
APPLICATIONS, FILES, OR OPERATING SYSTEMS.
EXAMPLES OF PRODUCTS WITH INVISIBLE EMBEDDED
SYSTEMS ARE THE CONTROLLER THAT RUNS A MICROWAVE OVEN
OR THE ENGINE CONTROL SYSTEM OF A MODERN AUTOMOBILE.

3. 1) A/D converter:
A hardware device that reads an analog signal—typically a
voltage—compares it to a reference signal, and converts the resulting
percentage to a digital value.
2) ABEL (Advanced Boolean Expression Language):
A design language for creating the logic to be implemented in a
simple programmable logic device. Programs created with ABEL are compiled
into the binary pattern necessary to create the PLD with a device programmer.
3) Address bus : A set of wires connected to a processor and all of the peripherals
with which it communicates, for the purpose of selecting a specific memory
location or register within a particular peripheral. If the address bus contains n
electrical lines, the processor can address up to 2n
unique locations. Address
decoding logic between the processor and the devices connected to the bus
select the proper device, typically based on the uppermost bits.

4. 4) Active low :
Denotes a logic device or circuit where a logic 1 is a lower voltage
than a logic 0.
5) Aliasing :
Allowing one memory location or register to be accessible at more
than one address. Aliasing is a result of address decoding and often happens with
peripheral control and status registers.
For example, if an I/O device has just four byte-wide registers but is mapped
into a 256-byte region of memory, aliasing will occur. In this case, the same four
registers can be read or written at any of 64 different locations within that region.

5. 6) Analog:
Analog is the way the world beyond the quantum level works. Part of
the challenge of digital engineering is to convert noisy, inaccurate, and ugly real-
world data to the pristine purity of 1s and 0s. The last two decades have seen a
massive growth in digital signal processors, partly because they allow us to replace
analog circuits with digital. Ultimately, the goal is to push the digital components all
the way back to all systems' front ends--essentially connecting a radio's antenna,
for example, directly into a DSP input.
7) Anode:
The element of a semiconductor device that accepts electrons. In a
diode, for example, current passes from the anode to the cathode. On a diode, the
anode is the terminal not marked by a band.

6. 8) Assembler:
A software development tool that translates human-readable
assembly language programs into machine-readable code that the target processor
can understand and execute.
9) Aperiodic server:
A task that responds to events of an application software
10) Application-specific integrated circuit [ASIC] :
A piece of custom-designed hardware in a mass-produced chip.
11) ARM [Advanced RISC Machine] :
A 32-bit RISC processor widely used in low-power embedded
applications.

7. 12) Aperiodic:
The term is most often used in the embedded context when
scheduling periodic tasks. The issue of what to do about aperiodic tasks and
interrupts inevitably arises in real-world systems. Aperiodic tasks become ready to
run on the occurrence of unpredictable events.
13) Assembly language:
A human-writable form of a processor's native
instruction set. In its typical form, each line of assembly code represents a single
CPU instruction. The human-readable representation of each opcode is called a
mnemonic.

8. 14) BASIC Stamp:
A tiny single-board computer manufactured by Parallax based
on an 8051, PIC, or other microcontroller. The BASIC Stamp is about the size of a
postage stamp (hence the name) and executes a variant of BASIC called PBASIC.
Inexpensive, self-contained, and easy to program, they're used in education and
simple embedded systems that require little horsepower but rapid delivery.
15) Bidirectional:
Describes a type of device or bus that supports two-way data
transfers. To reduce wiring, connectors, and pin counts, it's common to share data
on one bus. Data can move from device A to B or from B to A, though not at the
same time.

9. 16) Binary semaphore:
A type of semaphore with just two states. Often used to
guarantee mutual exclusion.
17) Breakpoint:
A location in a program at which execution is to be stopped and
control of the processor switched to the debugger. Mechanisms for creating and
removing breakpoints are provided by most debugging tools.
18) Compiler:
A software-development tool that translates high-level language
programs into the machine-language instructions that a particular processor can
understand and execute.

10. 19) Complex instruction set computer [CISC]:
Describes the architecture of a processor family. CISC
processors generally feature variable-length instructions and multiple addressing
formats and have a small number of general-purpose registers.
Intel's 80x86 family is the quintessential example of CISC.
20) Complex programmable logic device (CPLD):
A larger, more capable PLD. Each CPLD typically consists of
several programmable logic blocks plus a matrix of programmable interconnecting
paths. CPLDs can be used to create larger and more advanced logic circuits than
PLDs.

11. 21) Cross-compiler:
A compiler that runs on a different platform from the one for which it
produces object code. Often even the processor architecture/family of the host and
target platforms differ.
22) Deadline: In a real-time system, the time at which a particular set of
computations or data transfers must be completed. There are typically
consequences associated with missing a deadline. If the deadline absolutely,
positively must be met every time or else, it is called a hard deadline. Hard
deadlines have dire consequences when missed. Other deadlines are said to be soft
deadlines.

12. 23) Emulator:
Any debugging tool that pretends to be a system resource and adds
additional functionality or remote visibility.
24) Endianness:
The attribute of a hardware or software architecture that indicates how
multibyte values are represented and stored. The two possibilities are called big-
endian and little-endian.
25) Firmware:
This term is interchangeable with embedded software and sometimes is
used even when the executable is not stored in ROM.