MICRO DA Vellore Institute of Technology CSE 2006

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NIKHIL PANDEY 17BCE0100 1. How is 8255 –PPI (Programmable Peripheral Interface) constructed if its control register contains 9Ch & 8Dh. Answer PPI 8255 is a general purpose programmable I/O dev... ice designed to interface the CPU with its outside world such as ADC, DAC, keyboard etc. We can program it according to the given condition. It can be used with almost any microprocessor. It consists of three 8-bit bidirectional I/O ports i.e. PORT A, PORT B and PORT C. We can assign different ports as input or output functions. Block Diagram - This study source was downloaded by 100000855356755 from CourseHero.com on 11-01-2022 05:14:15 GMT -05:00 https://www.coursehero.com/file/57219012/MICRO-DApdf/ It consists of 40 pins and operates in +5V regulated power supply. Port C is further divided into two 4-bit ports i.e. port C lower and port C upper and port C can work in either BSR (bit set rest) mode or in mode 0 of input-output mode of 8255. Port B can work in either mode or in mode 1 of input-output mode. Port A can work either in mode 0, mode 1 or mode 2 of input-output mode. It has two control groups, control group A and control group B. Control group A consist of port A and port C upper. Control group B consists of port C lower and port B. Depending upon the value if CS’, A1 and A0 we can select different ports in different modes as input-output function or BSR. This is done by writing a suitable word in control [Show More]

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