As an example, the value of 1 001, if the interpretation is that it is a 2's complement fraction will be as follows -It is 1.001 assuming the binary point after the MS bit. As the MS bit is 1, it is a negative number. Then the remaining bits do not specify the magnitude directly. The 2's complement of 1 001 is 0110+ 1 = 0 111. This is a positive fraction with the value 1 × 2−1 +1 × 2−2 +1 × 2−3 = 0.5 + 0.25 + 0.125 = 0.875 decimal. Thus, -0.875 is the value of 1001.If ... Read More

To represent fractions may be necessary quite often inside the computer. For example, it may be needed to represent inside a computer a value like +0.610 or -0.610. To represent signed fractions, it is necessary to assume the binary point just after the MSB in the bit sequence. Such numbers where the binary point is assumed to be at a fixed position in the bit sequence are called fixed-point numbers.Unsigned fractions will have the assumed binary point at the extreme left. SM, 1's complement, and 2's complement fractions will have this imaginary binary point just to the right of the ... Read More

This is one of the methods of representing signed integers in the computer. In this method, 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.If the MSD is a 1, this indicates that the number is negative.The other bits indicate the magnitude (absolute value) of the number.If the number is negative, the other bits signify the 2'scomplement of the magnitude of the number.Thus a positive number has the same representation in SM, 1's complement, and 2's complement notations. Only negative numbers are represented ... Read More

This is one of the methods of representing signed integers in the computer. In this method, the most significant digit (MSD) takes on extra meaning.If the MSD is a 0, we can evaluate the number just as we would interpret any normal unsigned integer.If the MSD is a 1, this indicates that the number is negative.The other bits indicate the magnitude (absolute value) of the number.If the number is negative, then the other bits signify the 1's complement of the magnitude of the number.Some signed decimal numbers and their equivalent in 1's complement notations are shown below, assuming a word ... Read More

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