Member Avatar for ehsanelahimirza

hi all

i want to get system time outof com/serail ports of pc and then to display it on 7 segment LEDs

plz help me how to do serial communicationin assembly for port nad then which hardware is used outside to convert this serial data into parallel

  • 2 Contributors
  • 1 Reply
  • 81 Views
  • 1 Week Discussion Span
  • Latest Post Latest Post by oRg
Member Avatar for oRg

I remember doing something very similar in my assembly class a few years back.

We were using the old 8086/8088 Intel Developer Boards (circa 1979), and I remember we had to use the "in" and "out": commands in order to communicate with the serial port.

Here's some examples:

MOV 	DX, 800EH	; Assigns the input port address to register DX
IN	AL, DX		; Reads the input from port DX, and stores it into AL
MOV	DATA_7, AL	; Moves the contents of AL into DATA_7

and here's one of the OUT command

MOV	DX, 8000H	; Initialize the address of port 0
MOV	AL, 00H		; Load data with bit 7 as logic 0
OUT	DX, AL		; Output the data to port 0

Now, I'm pretty sure these examples work in MASM, and on the Intel 8086/8088 SDK. I got them from my old Assembly book written by Avtar Singh

I'm assuming they should work because Intel just built upon the 8086 instructions to make the x86 instructions we know today. Don't quote me on it though. It's been awhile so I'm a bit unsure. It can't hurt to try it though :)

Have fun.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.