Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
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:
AAD: ASCII Adjust for Division though the names of these 2 instructions (AAM and AAD) seem to be same, there is many difference between their functions. The AAD instruction conver
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
Modes of 8254 : Mode 0 (Interrupt on Terminal Count)-GATE which value is 1 enables counting and GATE which value is 0 disables counting, and GATE put not effect on
Hand shaking : Handshaking, or 2-way handshaking, is 1 type of strobe operation. It typically involves 2 handshaking lines: an output line to denote when the board is ready an
Software Interrupts Software interrupts are the result of an INT instruction in an executed program. It may be assumed as a programmer triggered event that immediately stops e
program to find negative and positive integers from given signed numbers with output and explanation of every instructions.
Pin functions for the minimum mode operation of 8086 are following: 1) M/I/O -Memory/IO: This is a status line logically equivalent to S2 in maximum mode. When it is low, it
take an integer and its base and the base in which you want to convert the number from user and perform conversion.
Fourth Generation Microprocessor : The single chip 32-bit microprocessor was introduced in 1981 by Intel as iAPX 432. The other 4th generation microprocessors were; Hewlett
General terms for Cache : Cache Hits : When the cache consisted the information requested, the transaction is said to be a cache hit. Cache Miss : When the cache does n
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd