Found 409 Articles for Microcontroller

The sign-magnitude binary format is the simplest conceptual format. In this method of representing signed numbers, the most significant digit (MSD) takes on extra meaning.If the MSD is a 0, we can evaluate the number just as we would any normal unsigned integer. And also we shall treat the number as a positive one.If the MSD is a 1, this indicates that the number is negative.The other bits indicate the magnitude (absolute value) of the number. Some of the signed decimal numbers and their equivalent in SM notation follows assuming a word size of 4 bits.Signed decimalsign-magnitude     +6   0110    ... Read More

Signed integers are numbers with a “+” or “-“ sign. If n bits are used to represent a signed binary integer number, then out of n bits, 1 bit will be used to represent a sign of the number and rest (n - 1)bits will be utilized to represent magnitude part of the number itself.A real-life example is the list of temperatures (correct to nearest digit) in various cities of the world. Obviously they are signed integers like +34, -15, -23, and +17. These numbers along with their sign have to be represented in a computer using only binary notation ... Read More

Unsigned binary integers are numbers without any ‘+’or ‘-’ sign. Here all bits representing the number will represent the magnitude part of the number only. No bits will remain reserved for sign bit representation. An unsigned binary integer is a fixed-point system with no fractional digits.Some real life Examples are −Number of tables in a class, The number of a member of a family.Obviously, they are unsigned integers like 10 and 5. These numbers have to be represented in a computer using only binary notation or using bits.Numbers are represented in a computer using a fixed size, like 4, 8, ... Read More

The Intel 8253 is programmable Interval Timers (PTIs) designed for microprocessors toper form timing and counting functions using three 16-bit registers. Each counter has 2 input pins, i.e. Clock & Gate, and 1 pin for“OUT” output. To operate a counter, a 16-bit count is loaded in its register. On command, it begins to decrement the count until it reaches 0, then it generates a pulse that can be used to interrupt the CPU.Features of 8253It has three independent 16-bit down counters.It can handle inputs from DC to 10MHz.These three counters can be programmed for either binary or BCD count.It is ... Read More

The Intel 8279 is used for keyboard interfacing but it can also be used for multiplexed 7-segment LED display interfacing. To display a character into 7-segment display we have to store 7-segment code in a display RAM location. The display RAM of this chip can store 16 bytes of data.Write to Display RAMTo write to the display RAM one special command is needed to be applied on the 8279 control port. The following pattern is showing the RAM command that is written to the control port of 8279.100AiAAAAThe first three bits are 100. It indicates ‘ Write to Display RAM’command. ... Read More

Here we will see how 8279 Chip can be used to interface a matrix keyboard with 8085 microprocessors. This chip can be used either keyboard/display interfacing mode or as a strobed input port. But generally, it is used as keyboard interfacing.The keyboard interfacing schemes can also be divided into two modes. These modes are Decoded mode of operationEncoded mode of operationDecoded Mode of OperationIn this mode, the matrix keyboard can have only four rows. These four rows can be selected by using SL3-0 select lines. There are eight columns. These can be selected using RL7-0 these eight column lines. So there are ... Read More

In this section, we will see how to connect a stepper motor with Intel 8051 Microcontroller. Before discussing the interfacing techniques, we will see what are the stepper motors and how they work.Stepper MotorStepper motors are used to translate electrical pulses into mechanical movements. In some disk drives, dot matrix printers, and some other different places the stepper motors are used. The main advantage of using the stepper motor is the position control. Stepper motors generally have a permanent magnet shaft (rotor), and it is surrounded by a stator. Normal motor shafts can move freely but the stepper motor shafts move ... Read More

The 8251 chip is Universal Synchronous Asynchronous Receiver Transmitter (USART). It acts as a mediator between the microprocessor and peripheral devices. It converts serial data to parallel form and vice versa. This chip is 28 pin DIP.The pin description of 8251A chipPinDescriptionD0 - D7parallel dataC/DControl register or Data buffer selectRDRead ControlWRWrite controlCSChip SelectCLKclock pulseRESETResetTxCTransmitter ClockTxDtransmitted dataRxCReceiver ClockRxDReceiver DataRxRDYReceiver ReadyTxRDYTransmitter ReadyDSRData Set ReadyDTRData Terminal ReadySYNDET/Synchronous Detect/BRKDETDetectBreakRTSRequest to send DataCTSClear to send DataTxEMPTYTransmitter EmptyVccVcc (5V)GNDGround(0V)Now let us see the functional block diagram of the 8251 chip.There are five different sections in this diagram. These sections are as follows −Read/ Write control logicTransmitter ReceiverData Bus ... Read More

In this section we will see how ADC (Analog to Digital Converter) works with Intel 8085 Microprocessor. The Analog to Digital Conversion is a quantizing process. Here the analog signal is represented by equivalent binary states. The A/D converters can be classified into two groups based on their conversion techniques.In the first technique it compares given analog signal with the initially generated equivalent signal. In this technique, it includes successive approximation, counter and flash type converters. In another technique it determines the changing of analog signals into time or frequency. This process includes integrator-converters and voltage-to-frequency converters. The first process ... Read More

In this section we will see how DAC (Digital to Analog Converter) using Intel 8051 Microcontroller. We will also see the sinewave generation using 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. These two methods are binary weighted method and R/2R ladder method. In this article we will use the MC1408 (DAC0808) Digital to Analog Converter. This chip uses R/2R ladder method. This method can achieve a much higher degree of precision. DACs are judged by its ... Read More