8251 programmable/communication interface-microprocessor, Assembly Language

Assignment Help:

8251 Programmable/Communication Interface

As an instance of a serial interface device let us suppose Intel's 8251 A programmable communication interfaces. The 8251A is diagrammed in given figure. It is capable of being programmed for synchronous / asynchronous communication.  The data that is in buffer and data-out buffer registers share the similar port address. For input, the serial bit stream is arriving on the R x D pin is shifted into the receiver shift register and then the data bits are transferred to the data-in buffer register, where they might be input by the CPU. On the other hand on output the data bits put in the data-out buffer register by the CPU are transferred to the transmitter shift register and, along with the essential synchronization bits, are shifted out through the T x D pin. Among other things the contents of the mode register, which are begin by the executing program, determine whether the 8251A is in synchronous mode or asynchronous mode and the format of the characters being received and transmitted. The control register, which is set by the program, controls the operation of the interface, and the status register makes sure information available to the executing program. Obviously, the sync character registers are for storing the sync characters required for synchronous communication.

1142_8251.jpg

Even though all 7 of the registers on the left side of Figure 4.7 may be accessed by the processor, the 8251A is associated with only 2 port addresses. The C/D pin is linked to the address line AO and AO differentiates the 2 port addresses. The 8251A internally interprets the C/D, RD, and WR signals as follows:

1611_8251 signals.jpg


Related Discussions:- 8251 programmable/communication interface-microprocessor

Base convertor, take an integer and its base and the base in which you want...

take an integer and its base and the base in which you want to convert the number from user and perform conversion.

Computer organization, write a program using assembly language that print y...

write a program using assembly language that print your name

Program to perform one byte bcd addition-assembly program, Program : Write...

Program : Write a program to perform a one byte BCD addition. Solution : It is consider that the operands are in BCD form, but the CPU considers it as hexadecimal and acco

Ror-logical instruction-microprocessor, ROR : Rotate Right without Carry: ...

ROR : Rotate Right without Carry: This instruction rotates the contents of destination operand to the bit-wise right either by one or by the count specified in register CL, exclud

Zero flag, Zero flag: The next line compares the value in register. A ...

Zero flag: The next line compares the value in register. A with the value 1. If they are equivalent, the Zero flag is set (to 1). The next line then jumps to start: only if th

CONSTANTS, Ask question #MinimuWHAT ARE CONSTANTS AND WHAT DO THEY DO?m 100...

Ask question #MinimuWHAT ARE CONSTANTS AND WHAT DO THEY DO?m 100 words accepted#

Sub-arithmetic instruction-microprocessor, SUB: Subtract :- The subtract in...

SUB: Subtract :- The subtract instruction subtracts the source operand from destination operand and result is left in the destination operand. Source operand might be memory locati

Synchronous and asynchronous transmissions of 8251, Typical link to modems ...

Typical link to modems for synchronous and asynchronous transmissions are shown in Figure. With regard to the synchronous connections it is consider that the timing is controlled

Write a program, write a program that calculates the fibonacci series: exce...

write a program that calculates the fibonacci series: except for the first two numbers in the sequence

Help with assemly language assignment, Will be needing help with assembly l...

Will be needing help with assembly language assignments over the course of 4 weeks

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd