Free Electronic Circuits & 8085 projects

Electronic projects with circuit diagram and 8085 microprocessor projects.

Receive message using 8251

Statement:Write a assembly program to receive 25 bytes from an CRT terminal to 8085 for the following requirements.

i) Baud rate x 16

ii) Stop bits 2

Status Word:

67.aReceive message using 8251 

67.bReceive message using 8251

Note: Reading of status word is necessary for checking the status of RxD line of 8085 that whether receiver is ready to give data or not.

Source program:

  • LXI H, 2300 H : Initialize memory pointer
  • MVI C, FFH : Initialize counter to accept 25 characters
  • MVI A, 00H
  • OUT FFH
  • OUT FFH : Dummy mode word
  • OUT FFH
  • MVI A, 40H : Reset command word
  • OUT FFH : Reset 8251 A
  • MVI A, CAH : Mode word initialization
  • OUT FFH
  • MVI A, 14 H : Command word initialization
  • OUT FFH
  • CHECK: IN FFH
  • ANI 02 H : Check RxRDY
  • JZ CHECK : Is RxRDY ? If not, check again
  • IN FEH : Get the character
  • MOV M, A : save the character
  • INX H : Increment memory pointer
  • DCR C : Decrement memory pointer
  • OUT FEH : Send character to the transmitter
  • JNZ CHECK : If not zero, accept next character
  • HLT : Stop program execution

Flowchart for Source Program

67.c-Receive message using 8251 

Related Programs (Click down)

Generate and display binary up counter

Generate and display BCD up counter with frequency 1Hz

Generate and display BCD down counter

Generate and display the contents of decimal counter