Introduction to Interrupt System Microprocessor and Interfacing by Ravinder Nath Rajotiya - March 27, 2020April 6, 20200 Interrupts Interrupt is one of the most common methods for an external device to communicate with the processor. In small systems, for example, we might read ASCII characters on interrupt basis, count interrupt from a timer to produce real time clock or seconds, minutes and hours; detect several emergency conditions on interrupt basis. Figure-1 below shows a general concept of the interrupt in our day-to-day activity. Suppose we are enjoying listening to music, if now phone bell rings, we stop or pauses our music and attends the phone, after conversation is completed, we again restart the paused audio and continue to listen the music. We would not our audio every minute to check if phone bell is ringing, which would be an inefficient
8255 PPI(Programmable Peripheral Interface) Microprocessor and Interfacing by Ravinder Nath Rajotiya - March 26, 2020April 21, 20220 8255 Programmable Peripheral Interface 8255 is a programmable peripheral interface IC which is used as an interface between the external device and the microprocessor for parallel communication. This IC is a 40-pi IC having three ports known as Port-A(PA), Port-B(PB) and Port-C(PC). these ports can operate in various modes. the complete details is given in the following PPTSs. Features of the 8255: It provide three I/O ports All the three I/O ports are latched Port operation is configurable by programming 8255 i.e. writing a control word in CWR BSR- bit set-reset mode allows individual pins of port C to be controlled to be set or reset. PIN diagram of 8255 8255 PPI is a 40-pin IC, it has three 8-bit ports named PA, PB
Introduction to Network parameters Network Analysis by Ravinder Nath Rajotiya - March 26, 2020April 6, 20200 A network is an interconnection of basic electrical elements. A network is called an electric circuit when it has current and voltage sources connected to it. Thus an electric is a closed energized network. Figure below shows an electric network and an electrical circuit.A Terminal is an entry or exit point for a current, and a port is a two terminal contacts where current or potential sources are connected or measured. Terminals are used in pairs. Introduction to Network Parameters PDF
8254 Software-Programmable Timer/Counter Microprocessor and Interfacing by Ravinder Nath Rajotiya - March 26, 2020May 10, 20210 The Intel 8254 is a counter/timer device designed to solve the common timing control problems in microcomputer system design. It provides three independent 16-bit counters, each capable of handling clock inputs up to 10 MHz. All modes are software programmable. The 8254 uses HMOS technology and comes in a 24-pin plastic or CERDIP package. General The 8254 is a programmable interval timer/counter designed for use with Intel microcomputer systems. It is a general purpose, multi-timing element that can be treated as an array of I/O ports in the system software. The 8254 solves one of the most common problems in any microcomputer system, the generation of accurate time delays under software control. Instead of setting up timing loops in software, the programmer
hybrid (h) Parameter Network Analysis by Ravinder Nath Rajotiya - March 26, 2020April 6, 20200 Hybrid or h parameter.Widely used in modeling electronic components and circuits particularly the transistor. It is call hybrid because both the open and short circuit parameters are used.Here the difference with the Z and Y parameter is that we use voltage at one port and the current at the other port Hybrid (h) Parameters PDF