this is my code for serial communication using 8051 iam trying to send letter B on serial port but iam not getting any thig on heperterminal though all setting are ok .so not getting what the problem is.
ORG 000H MOV TMOD,#20H MOV TH1,#0FAH MOV SCON,#50H SETB TR1 MOV A,#'B' ACALL DELAY A_1: MOV SBUF,A H_1: JNB TI, H_1 CLR TI SJMP A_1 DELAY: MOV R0,#255 L1: DJNZ R0,L1 MOV R1,#255 L2: DJNZ R1,L2 RET end
'Baud' [Bd] is a name of a unit named after Emile Baudot, 'rate' means a speed.
Eric,
Try using google and doing a define:baud
Far more often than not, you'll get something along the lines of 'unit of signalling speed' and 'number of bits per second'.
When I last got stopped by the police for speeding, they said I was doing 39MPH in a 30MPH zone, they didn't say I was doing 39MPH speed in a 30MPH speed zone.
Change that to 'if I were to get stopped by the police' ;)
But at least the definitions claiming "number of bits per second" should be ignored since that is a very bad definition.
I tried Google before I answered, of course. I must confess that even the 'unit named after Emile Baudot' has been pasted from Wikipedia (you may have noticed that ;-), even though I knew that fact before. On the other hand, Wikipedia (not talking about Google or Internet itself) is not fully trustworthy source...
To Per Westermark: 'baud rate' and 'number of bits per second' or, to be more precise, [Baud] and [bits/s] are DIFFERENT things, both meaningful. Unlike [Baud], which includes "all costs", i.e. START-bit, STOP-bit, parity bit, etc., the unit [bit/s] means only the 'useful' information (the character itself) transferred per second.
Best regards, Eric
No, baud contra bits/s shouldn't consider bits including/excluding start/stop bits. It is the number of symbol transitions per second, so it might be the same as bits/s, but for example high-speed modems transfers more than one bit in each symbol by using phase and amplitude, i.e. bits/second is higher than your baud measure.
That is why I claimed that definitions equalizing bits/s and baud are wrong.
You are right.