Number System Representation Digital Logic and Computer Design by Ravinder Nath Rajotiya - September 21, 2022December 29, 20220 Data Representation Data in a digital computer is written in binary using one of the following representations. Unsigned Magnitude Representation Signed Magnitude 1’s Complement 2’s Complement however the 2's complement is best suited for the arithmetic operations. These are explained as follows. 1. Unsigned Number Representation In this representation all the bits represent only the magnitude of the number without consideration to the sign of the number. Example: D7 D6 D5 D4 D3 D2 D1 D0 Value Minimum Value 0 0 0 0 0 0 0 0 0 Maximum Value 1 1 1 1 1 1 1 1 2N-1 =255 The range of the numbers that can be represented in this representation is 0 to 2N-1 For a 4-bit number the range will be = 0 to 24-1 = 0 to 15 For an 8-bit number the range will be = 0 to 28-1 = 0 to 255 · Note: We cannot represent signed number in
1. Number System Digital Logic and Computer Design by Ravinder Nath Rajotiya - September 17, 2022September 17, 20220 What is a Number? A number is a mathematical value used for counting or measuring or labelling objects. In number system these numbers are used as digits. Number Systems A number system is the mathematical notation for representing numbers of a given set by using digits or other symbols in a consistent manner. It provides a unique representation of every number and represents the arithmetic and algebraic structure of the figure. The value of any digit in a number can be determined by: The digit Its position in the number The base of the number system Number System Chart There are various types of number systems in mathematics. The four most common number system types are: Decimal number system (Base- 10) Binary number system (Base- 2)
Interfacing DAC Microprocessor and Interfacing by Ravinder Nath Rajotiya - May 4, 2022May 4, 20220 Digital-to-Analog Conversion or simply DAC, is a device that is used to convert a digital (usually binary) code into an analog signal (current, voltage, or electric charge). Digital-to-analog conversion is the primary means by which digital equipment such as computer-based systems are able to translate digital data into real-world signals that are more understandable to or useable by humans, such as music, speech, pictures, video. It also allows digital control of machines, equipment, household appliances. When data is in binary form, the 0's and 1's may be of several forms such as the TTL form where the logic zero may be a value up to 0.8 volts and the 1 may be a voltage from 2 to 5 volts. The
Interfacing LCD Microprocessor and Interfacing by Ravinder Nath Rajotiya - May 4, 2022May 4, 20220 Introduction LCD is the most common display devices used in different dedicated applications be it the instrumentation, medical equipment, panels, robotics etc. It is quite easy to interface it with the microprocessors or microcontrollers. We can directly interface a LCD with microcontrollers, however, for interfacing with microprocessors, we need a peripheral device such as 8255. Here in this post we discuss the basics of LCD, its commands, interfacing using 8255 PPI an final a program to initialize LCD to display some user data on it. PIN Diagram of LCD Pin number Symbol I/O Description 1 Vss xx GND 2 Vcc xx +5V 3 VEE Xx Power Supply to control contrats (use POT) 4 RS I RS=0 to select command Register, to allow user to send command to LCD RS=1 to select data register, allowing user to send data for display 5 R/W I R/W=0 : to Write R/W=1: to
Analog to Digital Conversion (ADC) interfacing Uncategorized by Ravinder Nath Rajotiya - May 2, 20220 ADC ADC is used to convert an analog input voltage to its digital equivalent. ADC chip family is ADC080X from National Semiconductors. Some of the ICs are: ADC-0800, ADC-0804: singly analog input channel and 8-bit out bits ADC-0808 and ADC-0809: These are eight analog input inputs with 3-select lines used to select one of eight channel. It also has 8-bit digital output. ADC-0816 : It is an 16-input channel and gives 8-bit digital output signal. Why Analog to Digital Signals in the real world are analog: light, sound, temperature, pressure, acceleration or other phenomenon. So, real-world signals must be converted into digital, using a circuit called ADC (Analog-to-Digital Converter), before they can be manipulated by digital equipment. When you scan a picture with a scanner what