http://www.8051projects.net/ Learn to make simple microcontroller projects, pic, 8051, avr and arm projects. download 8051 projects, tutorials, libraries, sample codes. join the microcontroller discussion forum and ask doubts regarding electronics. the best source for 8051 over internet. en-gb 2009-01-08T11:50:01-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t9408.html 2009-01-08T11:50:01-08:00 HI ALL, I work with MCU 1 st time and i have a problem in programming UART transmisionThat my programe is to send 0xff and ON indication LED then OFF the LED for 1 secbut i found that the LED ON forever ,pls check my programme.i use at90s8515 with 8mhz crystaland that my programme.........CODE:LDI R18,0X80   ;STACK POINTER
OUT $3D,R18

SBI $11,4      ;O/P LED INDECATION

LDI R16,51     ;9600 BOUD RATE @8MHZ
OUT $09,R16

NEXT:
SBI $12,4                       ;LED ON
LDI R31,HIGH(2*ASD)
LDI R30,LOW(2*ASD)
RCALL STRANSMIT
RCALL DELAY1
CBI $12,4                       ;LED OFF
RCALL DELAY1
RJMP NEXT

DELAY1:                           ;ONE SEC DELAY
ldi r20, 20
ldi r21, 255
ldi r22, 255
DELAY:
dec r22
brne DELAY
dec r21
brne DELAY
dec r20
brne DELAY
ret

STRANSMIT:
SBI $0A,3                         ;TXEN  UCR(3)=1
AGAIN1:
LPM R20,Z
CPI R20,0                        ;COMBAR WITH LAST ZERO
BREQ QUIT
OUT $0C,R20                      ;DATA IN UDR
W:
SBIS $0B,5    ; ?
RJMP W
ADIW R31:R30,1
RJMP AGAIN1
QUIT:
CBI $0A,3
RET


ASD: .DB 0XFF
     .DB 0
  http://www.8051projects.net/forum-t9408.html 2009-01-08T11:50:01-08:00 Ajay I think you cannot use this instructionLPM R20,Zcoz you are using 8515 so only LPM is allowed without operands. http://www.8051projects.net/forum-t9408.html 2009-01-08T11:50:01-08:00 ENG\ AHMED great thx ........... AJAY