What is a Microcontroller ?
Microcontrollers is the main element of a computer system, which contains a single
chip. They have memory, IO and CPU on the same chip. This is intended to reduces
size and also increases performance and flexibility.
What is a Digital to Analog Converter (DAC)?
The Digital to Analog converter (DAC) is a device, that is widely used for converting
digital pulses to analog signals. There are two methods of converting digital signals to
analog signals.
How to use Digital to Analog converter(DAC) in a Microprocessor
A computer is a binary machine operating in an analog world, so to be able to produce
an output that is understandable by other devices a DAC is used.
(1) Modem :
A modem is a device that translates digital signals from a computer into analog form
so that they can be transmitted over analog telephone lines. The modem also translates
analog signals back into digital form for the receiving computer.
This frequency is transmitted over a line, frequently as an audio signal over a
telecommunications line, to another modem that converts it back into a copy of the
original data.
Synchronous data transmission uses timing signals in the data stream along with
transmitted bits of uniform duration and interval. This permits the receiving modem to
ignore spurious signals that do not conform to the anticipated signal. Asynchronous
data transmission relies instead on various error-correcting protocols. Although most
modems are either of the synchronous or asynchronous variety, some employ both
methods of communication. Wireless modems send or receive data as a radio signal.
Modems were first used with teletype machines to send telegrams and cablegrams.
Digital modems were developed from the need to transmit large amounts of data for
North American air defense during the 1950s. The first commercial modem was
introduced in 1962. Dennis C. Hayes invented the personal computer modem in 1977,
marking the emergence of the online and Internet era. In the beginning modems were
used primarily to communicate between data terminals and a host computer. Later the
use of modems was extended to communicate between hosts in networks. This
required modems that could transmit data faster, leading to the introduction of
compression techniques to increase data rates and error detection and correction
techniques to improve reliability. However, still faster transmission speeds were
required.
(2) Video Adapter:
A video adapter is a board that plugs into a personal computer to give it display
capabilities. The display capabilities of a computer, however, depend on both the
logical circuitry (provided in the video adapter) and the display monitor. A
monochrome monitor, for example, cannot display colors no matter how powerful the
video adapter. many different types of video adapters are available for pcs. Most
conform to one of the video standards defined by ibm or vesa.
each adapter offers several different video modes. The two basic categories of video
modes are text and graphics. In text mode, a monitor can display only ascii characters.
In graphics mode, a monitor can display any bit-mapped image. Within the text and
graphics modes, some monitors also offer a choice of resolutions. At lower
resolutions a monitor can display more colors.
modern video adapters contain memory, so that the computer’s ram is not used for
storing displays. In addition, most adapters have their own graphics coprocessor for
performing graphics calculations. These adapters are often called graphics
accelerators. video adapters are also called video cards, video boards, video display
boards, graphics cards and graphics adapters.
How to use Analog to Digital converter(ADC) in a Microprocessor
What is an Analog to Digital Converter (ADC)?
Analog To Digital Converter (ADC) allows micro-processor controlled circuits to
communicate with the real world. In the real world, analogue signals have
continuously changing values which come from various sources and sensors which
can measure sound, light, temperature or movement, and many digital systems
interact with their environment by measuring the analogue signals from such
transducers. Examples of Analog devices are: temperature, pressure, liquid levels and
light intensity.
Applications
1. Digital Oscilloscopes and Multimeter
The greatest advantage of analog oscilloscopes is that there’s very little ‘circuitry’
between the input connector and the screen, in other words you see exactly what’s
going on in a circuit in real time. However, they cannot store waveforms for later use
or perform on-board measurements.
Digital oscilloscopes overcome all these problems and at their heart lies a very
powerful and fast ADC with a resolution of 12 bits and above. The ADC converts the
waveforms to a binary value that can be stored in memory, operated upon and
displayed on a screen.
2. Microcontrollers
Almost all modern microcontrollers have a built in ADC, the most common being the
Arduino based on the ATMega328P with a 10 bit resolution and the STM32 with a 12
bit resolution.The Arduino IDE provides a useful ‘analogRead()’ function that reads
an analog voltage on one of the analog pins and returns a 10 bit integer value, i.e. a
range of 0 to 1023.
Assignment on Cos 203
By: ISHIWU ERNEST C
Department: Computer Science
Reg No: 2019/250635
Date: 08/02/2021