8254: Programmable Interval Timer 1. Draw the pin diagram and functional block diagram of 8254. Ans. The pin diagram and functional block diagram of 8254 are shown below: 2. How many counters are there in 8254? Ans. There are three 16-bit counter registers, each of which can be programmed as a timer or an event […]
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Microprocessors And Peripheral ICs Questions And Answers
8155/8156: Programmable I/O Ports and Timer
8155/8156: Programmable I/O Ports and Timer 1. In what way 8155 and 8156 differs? Ans. The Chip Enable (CE) signal is active low for 8155, whereas it is active high for 8156. 2.What are the essential features of 8155. Ans. The essential features of 8155 are *8-bit 256 word RAM memory *Two programmable 8-bit I/O […]
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8279: Programmable Keyboard/Display Interface
8279: Programmable Keyboard/Display Interface 1. Draw the pin diagram of 8279. Ans. The pin diagram of 8279 is shown below: Fig. 9d.1: 8279 pin diagram (Source: Intel Corporation) 2. Draw the functional block diagram of 8279 and elaborate on the different blocks. Ans. The functional block diagram of 8279 is shown below: The different functional […]
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8355/8755: Programmable I/O Ports with ROM/EPROM
8355/8755: Programmable I/O Ports with ROM/EPROM 1. Draw the pin connection diagram of 8355. Ans. The pin connection diagram of 8355 is shown in Fig. 9c.1. 2. Draw the functional block diagram of 8355 and discuss. Ans. The functional block diagram of 8355 is shown in Fig. 9c.2. 3. What is the difference between 8355 […]
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8255: Programmable Peripheral Interface
8255: Programmable Peripheral Interface 1. Draw the pin diagram of PPI 8255. Ans. The pin diagram of 8255 is shown in Fig. 9a.1 Fig. 9a.1: 8255 Pin diagram (Source: Intel Corporation) 2. Draw the block diagram of 8255. Ans. The block diagram is shown in Fig. 9a.2. 3. How many ports are […]
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Memory
Memory 1. What is a memory? Ans. A memory is a device that stores information in electrical, magnetic or optical form. A µC based system, which operates on digital logic, holds binary information. Semiconductor memories are used in µC based system. 2. Why semiconductor memories are used as main memories in mC based systems? Ans. […]
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Data Transfer Techniques: Interfacing Memories and I/Os
Data Transfer Techniques: Interfacing Memories and I/Os 1. Mention the two broad categories in which data transfer schemes are classified? Ans. The data transfer schemes are broadly classified into two categories. These are * Programmed data transfer * Direct Memory Access (DMA) transfer. 2. Mention the types of programmed data transfer. Ans. Programmed data transfer […]
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Stack and Subroutines
Stack and Subroutines 1. What is a stack? Ans. A stack is a group of memory locations in the R/W memory. 2. Why stack is used in a program? Ans. The stack is used to store information temporarily during the execution of a program. Also the stack is used in subroutine calls to store the […]
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Programming Techniques
Programming Techniques 1. Explain DAA instruction. Ans. It stands for ‘decimal adjust accumulator’. Execution of DAA instruction converts the content of the accumulator into two BCD values. The system utilises the AC flag (not accessible by the programmer, but is used internally for DAA operation) for this conversion by following the procedures stated below: (a) […]
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8085 Interrupts
8085 Interrupts 1. Mention the interrupt pins of 8085. Ans. There are five (5) interrupt pins of 8085—from pin 6 to pin 10. They represent TRAP, RST 7.5, RST 6.5, RST 5.5 and INTR interrupts respectively. These five interrupts are ‘hardware’ interrupts. 2. Explain maskable and non-maskable interrupts. Ans. An interrupt which can be disabled […]
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