Strange glitch

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labrat31

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I have almost finished writing a program to receive and transmit strings of data. It reads a 4 byte data string from UART and sends it to RAM then transmits the data from RAM in a 4 byte string back over UART. It also has a timer so it will not lock up or loose sync if it reads 3 or 5 bytes. It works ok say 90% of the time other then this glitch, when I send data to the micro from a computer continuously with a delay in between strings say 100 mS sometimes it will miss a string and the ports flick on and off quickly even though I have no reference to ports in the program. Anyone know what this could be??
 
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Code: 
;
;#####  Receive and transmit       #####	
;#####  strings of data over UART   #####


 
 
	serTx	DATA	    30H
	serRx	DATA	    31H

	byte1	DATA	    32h
	byte2	DATA	    33h
	byte3	DATA	    34h
	byte4	DATA	    35h


 			ORG 00h


;#####      Main program      #####



		ACALL SetUART	;Set up UART

		;set up pointers to load UART data string to RAM

loop:		MOV R0,#serRx	;source pointer			  	
		MOV R1,#byte1 	;destination pointer	
		MOV R3,#4 	;counte	
		ACALL Rx_ram	;input UART string to ram  


		;set up pointers to load RAM data to UART and output string 

		MOV R0,#byte1	;source pointer			  	
		MOV R1,#serTx	;destination pointer	
		MOV R3,#4 	;counte
		ACALL ram_Tx	;output string of data from ram over UART

		ACALL loop	   ;keep doing it in a loop

;####################################
;#####      	  RAM Loops        ######
;####################################



		
Rx_ram:		ACALL Rx		;Get data from UART 
		MOV A,@R0 		;get a byte from source
		MOV @R1,A 		;copy it to destination
		INC R1 			;increment destination pointer
		DJNZ R3,Rx_ram 		;keep doing till all bytes are received
		;setb P0.4		;turn off p0.4 LED after all bytes are sent
		RET

ram_Tx:		MOV A,@R0 		;get a byte from source
		MOV @R1,A 		;copy it to destination
		INC R0 			;increment source pointer
		ACALL Tx			;transmit data byte   
		DJNZ R3,ram_Tx 	;keep doing till all bytes are sent 
		RET




 
;####################################
;#####   UART Initialization   ######
;#####		&	   ######
;#####	 transmit and receive  ######
;#################################### 

 
setUART:		MOV	PCON,#0x80	;x2 serial baud rate
		MOV	TH1,#0xF4 	;reload value 250 for 9600bps w/11.059MHz xtal
		MOV	TL1,#0xF4 
		MOV TMOD,#0x20 	;timer 1,mode 2(auto reload)
		MOV	TCON,#0x40	;start timer 1
		MOV	SCON,#0x50 	;8-bit, 1 stop, REN enabled
		RET	
 
TstOK:		MOV serRx,SBUF				
		CLR RI			 ;clear RI flag
		RET

		;timer to keep sync

Rx:		MOV R4,#20	 	;delay time multiplier     
AGAIN:		MOV R5,#20	 	;delay time   
HERE:		JB RI,TstOK		;get byte from SBUF if IR is set 
		NOP
		NOP
		DJNZ R5,HERE
		DJNZ R4,AGAIN
		ACALL st_flt	 ;exit if there is no receive in time period  

		;transmit  UART
Tx:		MOV SBUF,serTx 	;saving incoming byte in A
TxH:		JNB TI,TxH 		;wait for the last bit		
		CLR TI 			;get ready to receive next byte
		RET				;Return to main program

st_flt:		NOP
		;CLR P0.4
		ACALL loop		;start loop again   



		END

its still a little messy and missing some comments but this is what I have so far

if u mean dose it use the Receive interrupt flag then yes. Im still self learning so I may be missing something

copying my code into “wrap code” messed up my formatting big time sorry but the .asm should look ok
 
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Should my sync timer be on interrupts? Trying to get it working now but the interrupt only works once

ORG 23H
LJMP ser_IE
ser_IE: MOV serRx,SBUF
CLR RI
AJMP Rx_bite
 
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