problem with serial port interfacing

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froten

New Member
Hello,

Im tring to write a program for AT89C51 that can send a stream of one character (which is 5) to the computer, I wrote this program but it doesn't work because I didn't see any signal going out from the Tx pin using the osciloscope. the program is as follows:

mov TMOD,#20
mov TH1,#-3
mov SCON,#50
SETB TR1
AGAIN:
mov a,"5"
acall TRANS
sjmp AGAIN
TRANS:
mov SBUF,a
HERE:
jnb TI,HERE
CLR TI
ret
end

the buad rate should be 9600 bps. I didn't actually connect the circuit to the computer because when I use the osciloscope I don't see any signal on the Tx pin. I have attached both the asm and hex files for more information.

Please any help on this issue is appreciated as it is very important for me to get it working.
 

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  • Serial.zip
    404 bytes · Views: 101
all i can give you right now is this file,

it helped me a lot when i was trying to setup the UART in my AT89C52..

**broken link removed**
 
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