Hi Robert,

Yes I am using Register 0 to set the count for the 25 bytes, code for where it is implemented in the subroutine is below it also calls WRITE_TABLE_SERIAL, R0 is set there, then decremented until = 0 in WRITE_TABLE_SERIAL

As for the accumulator it will hold the value 50H at the end of WRITE_SERIAL after bit TI is cleared. It doesnt necessarily need to be a specific value at end of WRITE_SERIAL because it will be overwritten once next byte is called (possibly bad practice?). I could maybe tell it to clear acc before it returns from subroutine in order for there to be no errors with the reading the next byte but single stepping didnt show any issues.

Another test, I tried to run it with another PC in my lab incase port was faulty on PC side, but got same results.

Sorry for not displaying all code at start.

Thanks

REQUEST_CONNECT:

			PUSH ACC
			CLR A
			MOV DPTR,#REQUEST_CONN				;MOVE DATA POINTER RQST_CONN TABLE
			MOV R0,#25H										;MOV R0 TO 25H TO ALLOW FOR THE 25 BITS IN TABLE
			LCALL WRITE_TABLE_SERIAL			;CALL WRITE_TABLE_SERIAL TO WRITE THE BYTES TO SBUF	
			MOV R1,#BUF										;LET R1 = LOCATION 40
			MOV R2,#25H										;LET R2 = SIZE OF PACKET TO BE COUNTED (25)
			LCALL READ_TABLE_SERIAL
			POP ACC
			RET