Unable to communicate through serial port

Dibyendu · 2007-07-10T12:15:31+00:00

Hi,I am new on this field, and taking this as hobby, but the real factis, I can't communicate my 8051 microcontroller board to my PC viaserial port. can any body help me for that issue??Specification of my board:8051 microcontroller: AT89C52 24pc.Cristal Oscillator: 11.0592 Mhz.Compiler: Keil.The code for the board:;----------------------------------------------------------------------------------------------------------------------------------------- org 0 mov TMOD, #20H ;timer 1, mode 2 mov TH1, #-3 ;9600 boud rate mov SCON, #50H ;8-bit, 1 stop bin, REN enabled setb TR1 ;start timer 1again: mov SBUF, #"X" ;letter "X" to be transferredhere: jnb TI, here ;wait for the last bit clr TI ;clear TI for next char sjmp again ; keep sending "X" ret end;-----------------------------------------------------------------------------------------------------------------------------------------On the PC side I am using a simple "turbo C" code [Downloaded :-) ]like://---------------------------------------------------------------------------------------------------------------------------------------#include #include #include #define PORT1 0x3F8void main(void){ int c; int ch; outportb(PORT1 + 1 , 0); /* Turn off interrupts - Port1 */ /* PORT 1 - Communication Settings */ outportb(PORT1 + 3 , 0x80); /* SET DLAB ON*/ outportb(PORT1 + 0 , 0x0C); /* Set Baudrate - Divisor Latch Low Byte */ /* 0x0C = 9,600 BPS */ outportb(PORT1 + 1 , 0x00); /* Set Baudrate - Divisor Latch High Byte */ outportb(PORT1 + 3 , 0x03); /* 8 Bits, NoParity, 1 Stop Bit */ outportb(PORT1 + 2 , 0xC7); /*...

Jul 10, 2007 24 Replies

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Roman 19 years ago

Yes, but virtual DOS session detects that DOS program is trying to communicate to COM port and simulates that.

If Windows simply locked up DOS programs, they would not work. I seen programs written in 1988 working under Win2k and WinXp and happily communicating over COM1.

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David Brown 19 years ago

That's certainly a more realistic comparison - but I think mine was a little more colourful! I did once use a cigarette lighter for soldering, but thankfully it was just a few wires and not SMD...

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cs_posting 19 years ago

I'm getting severly tempted to scare up a junk board at lunchtime, spread some paste, drop an 8 pin SMD package in it, and see if I can reflow it with a cigarette lighter as a heat source.

Except that the new car doesn't have one... it has an accessory jack with a little plastic door and no lighter in it.

Now what am I going to do when I need to make emergency repairs????

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Dibyendu 18 years ago

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Hi all, I had got success. (Because of the expert help from you all).

....... :-)

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robot2051 18 years ago

Hey ^^;; i'm new to this forum and also just started embedded programming I studied 68HC11 and 68HC12 in uni but at home i'm using a 8051. My un project that i'm thinking of doing involves serial port programming assembler and socket programing. I have a few knowledges of everything an kinda have an idea of how to put things together. At the moment, i'm trying to get my 8051 board + relays to control 2 A servos. I'm thinking of controlling it through the computer and the further on i would control it over the net with the help of socke programming. Do you know any good books that might help? I'm struggling with the seria port signal from PC to programming board too. Is it corrected to sort RT and CTS on PC side? Also, thank you for posting this thread and your draft program. I'm usin it as a reference to build my own now.

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