Match the following : Codes :List – I (Pin terminals) List – II (Applications) a. SID, SOD i. Wait state b. READY ii. Serial data transfer c. TRAP iii. Address Latch Control d. ALE iv. Interrupt
a-ii, b-i, c-iv, d-iii
Each pin's own name gives it away, so the match is a-ii, b-i, c-iv, d-iii — option 1.
| Pin | Expansion | Function |
|---|---|---|
| SID, SOD | Serial Input Data, Serial Output Data | ii. Serial data transfer |
| READY | — | i. Wait state |
| TRAP | — | iv. Interrupt |
| ALE | Address Latch Enable | iii. Address latch control |
SID and SOD are read and written by the RIM and SIM instructions respectively, letting software shift data one bit at a time — a serial port built from two pins and a delay loop, with no UART needed.
READY handles slow memory. The processor samples this pin during each machine cycle; if it is found low, the 8085 inserts wait states — idle clock periods during which the address and data lines are held steady — and keeps inserting them until READY goes high. A memory or peripheral too slow to answer within the normal cycle can therefore be used without slowing the whole system, since only accesses to that device are stretched.
TRAP is the highest-priority interrupt and has two properties the others lack: it is non-maskable, so neither DI nor SIM can disable it, and it is edge- and level-triggered, so a single noise spike cannot fire it. Both features suit its intended use for events that must never be ignored — power failure, most classically, where the routine has a few milliseconds to save the machine state before the supply collapses.
ALE solves the multiplexed-bus problem. The 8085 sends the low byte of the address and the data byte over the same eight pins, AD0–AD7, to save package pins. ALE goes high during the first clock state of every machine cycle, precisely while those lines carry the address, and the falling edge is used to clock an external latch — a 74LS373 or an 8212 — which then holds the address steady for the rest of the cycle while the same wires carry data.
Hence, the correct code is a-ii, b-i, c-iv, d-iii.
Similar Questions
A microprocessor is a semiconductor chip fabricated with entire central processing unit (CPU) on it. It is a programmable device that accepts binary data from an input device, processes the data according to the instructions stored in the memory and provides results as output. Basically microprocessor performs two functions - (a) Fetches an instruction from the memory and (b) Performs the operation specified by the instruction. There are special inputs to the microprocessor called interrupts. External devices use these interrupts to get the microprocessor attention. A micro computer can be built by using 8085 microprocessor along with many other chips such as 8155, 8255, 8279, 8253, 8257, 8259, 8251 etc. 8085 microprocessor is 8-bit microprocessor which has 8-bit data registers where as 8086 is a 16-bit microprocessor.
The following 8051 assembly program is given. Answer the questions based on it.
Line No. Mnemonics 1 MOV SP, #4F H 2 SET B PSW.3 3 MOV R0, #25H 4 MOV R1, #0AH 5 MOV R2, #06H 6 PUSH 8 7 PUSH 9 8 PUSH 0AH . . . V V 20 POP 8 $D_7$ $D_6$ $D_5$ $D_4$ $D_3$ $D_2$ $D_1$ $D_0$ In 8255 programmable peripheral interface device, if the port A and port B are to be set in a hand shake mode along with port C, what are the bits in the 8 bit control word to be set as 0 1 0.
The number system for the machine code of the microprocessor 8085 is
Which of the options in a multipurpose instruction used to implement the interrupt of 8085 and serial data input ?
Both 8155 and 8255 programmable peripheral interface ICs have the following common features :
(i) Programmable I/Os
(ii) Either port A or Port B can be set as either input or output ports.
(iii) One 14-bit down counter
(iv) AD0 – AD7 are multiplexed address/datalines.Each instruction in an assembly program has the following fields :
(i) Lable field
(ii) Operand field
(iii) Comment field
(iv) Mnemonic fieldPlease write the proper sequence of fields :
The mnemonic of 8085 processor indicate :
List – I List – II a. RLC i. Rotate Accumulator Right through carry b. RRC ii. Rotate Accumulator Left through carry c. RAR iii. Rotate Accumulator Left d. RAL iv. Rotate Accumulator Right Codes :
Assertion (A) : In serial communication system, when the transmission of data goes in both ways, it is called full-duplex system. Now if two micro processors are connected in full duplex mode, the amount of data transmitted will be double to the amount of data in half-duplex mode connection.
Reason (R) : When the transmission of data goes in one way, it is called half-duplex system and when the data moves in both ways, it is called full duplex system.
The assembler directive used to give name to some value or symbol for 8086 ASM-86 is
Important Questions from Microprocessors
An 8086 address bus is a/an _____ -bit bus
Program counter for any counter:
In the pin out configuration of the 8085 microprocessor, the sequential input data is represented by
Which of the following functions is not performed by a microprocessor?
Match the columns.
Pin
Description
a. D 0-D 7
1. Reset Input
b. RESET
2. Data Lines
c. A 0,A 1
3. Internal Address
