PART B (5 x 16 =80) 1. Explain with a help of neat diagram of Pin out details of 8085 microprocessor. Intel 8085 consists of 40 pins and signal can be classified as follow: Address Bus. Data Bus. Control and Status signals. Power supply and frequency signals. Externally initiated signals. Serial I/O ports. ADDRESS BUS The 8085 has eight signal lines, A15 A8 : Unidirectional, known as high order address. DATA BUS AD7 AD0: bidirectional and dual purpose (address and data placed once at a time). AD7 AD0 also known as low order addresses. To execute an instruction, at early stage AD7 AD0 uses as address bus and alternately as data bus for the next cycle. The method to be change from address bus to data bus known as bus multiplexing. Mr.P.SANTHOSH AP/Mech Page 1
CONTROL AND STATUS SIGNAL ALE This signal helps to capture the lower order address presented on the multiplexed address/data bus. The ALE (Address Latch Enable) signal enables the lower order address to be latched externally. RD Read (active low). To indicate that the I/O or memory selected is to be read and data are available on the bus. WR Write: Active low. This is to indicate that the data available on the bus are to be written to memory or I/O ports. IO/M To differentiate I/O operation of memory operations. 0 - indicates a memory operation. 1 -indicates an I/O operation. IO/M combined with RD and WR to generate I/O and memory control signals. S1 and S0: Status signals, similar to IO/M, can identify various operations as shown on the following table : S 1 S 2 Operations 0 0 HALT 0 1 WRITE 1 0 READ 1 1 FETCH POWER SUPPLY AND FREQUENCY SIGNALS Mr.P.SANTHOSH AP/Mech Page 2
EXTERNALLY INITIATED SIGNALS SERIAL I/O PORTS SID (Input) This is input signal is used to accept serial data bit by bit from the external device. SOD (Output) This is an output signal which enables the transmission of serial data bit by bit from the external device. RESET SIGNALS RESET IN: an active low input signal, Program Counter (PC) will be set to 0 and thus MPU will reset. RESET OUT: an output reset signal to indicate that the μp was reset (i.e. RESET IN=0). It also used to reset external devices. Mr.P.SANTHOSH AP/Mech Page 3
2. Explain the architecture of 8085 with the required diagrams. Also write the salient features of the same. Mr.P.SANTHOSH AP/Mech Page 4
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3. Draw and explain about the 8085 timing diagram. Mr.P.SANTHOSH AP/Mech Page 7
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4. (i) Write short notes on comparison between microprocessor & microcontroller. Mr.P.SANTHOSH AP/Mech Page 12
(ii) Classify and explain the Addressing modes of 8085. Mr.P.SANTHOSH AP/Mech Page 13
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5. Draw and explain the architecture of 8051 microcontroller. Mr.P.SANTHOSH AP/Mech Page 15
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6. Explain the classification of instruction set of the microprocessor 8085. Mr.P.SANTHOSH AP/Mech Page 19
7. Draw and explain the block diagram and operation of temperature controlling system with a microprocessor. Mr.P.SANTHOSH AP/Mech Page 20
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8. Draw and explain the block diagram and operation of Traffic light controller with a microprocessor. Mr.P.SANTHOSH AP/Mech Page 24
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9. Describe with neat diagram the stepper motor control using microprocessor. Mr.P.SANTHOSH AP/Mech Page 27
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