Hi everyone i am working on a control car project by using Atmel At89S51 8051 mircocontroller. By coding with assembly langugage , i figured out the MOV A,SBUF is not reading anything and send to Accumulator. Baud rate is 9600 with same as HC-05 bluetooth chip. Down there is my code, i ran debug from uKeil, by typing SBUF value it doesnt read and send to accumlator, i enabled RI too but it still didnt accept anything but keep in 00H
ORG 00H
MOV A,#00HMOV P2,AMOV TMOD, #20HMOV TH1, #-3MOV SCON, #50HSETB TR1
REPEAT:JNB RI, REPEATMOV A,SBUFCLR RICJNE A,#"F",ONEMOV P2,#89HSJMP REPEAT
ONE:CJNE A,#"B",TWOMOV P2,#86HSJMP REPEAT
TWO:CJNE A,#"L",THREEMOV P2,#8AHSJMP REPEAT
THREE:CJNE A,#"R",FOURMOV P2,#85HSJMP REPEAT
FOUR:CJNE A,#"C",REPEATMOV P2,#00HSJMP REPEATRETEND