| ??? 02/04/09 19:22 Read: times Msg Score: -1 -1 Message Not Useful |
#162069 - Horesfeathers! Responding to: ???'s previous message |
Dave Brooks said:
Recall from the first message in this thread, the OP said the following:
Hi, Can it possible to use 89c51> 6 MHz Crystal and can communicate with PC using serial port on 2400 Baud Rate of Speed. Some of the persons saying it is impossible >> you have to use 11.0592MHz to send the reports on serial port of PC using hyper terminal. Long back i seen one product based on 89c51 having crystal 6 MHz with serial interface and i seen the reports too. Please comment. A more concise translation of this message might be: Hi (friendly gesture, intended to introduce oneself) Is it possible to use a 6 Mhz crystal with an 89C51 microcontroller to generate a baud rate of at least 2400 bps? My application includes interfacing this microcontroller to a personal computer, over standard RS-232. My reason for asking is to clarify a disagreement between myself and my co-worker, who claims this kind of speed requires a minimum of 11.0592Mhz. A long time ago, I recall seeing a system, based on this very same microcontroller, that had a 6 Mhz crystal and it was able to achieve this speed. I just cannot recall where, and I am uncertain how to go about finding this out... Please, can anyone help me? (a humble request for help) This could also be interpreted as simple begging. There's a lot of that that goes on here, particularly when people have homework to do, and don't want to waste their own time doing it. Now, let's consider the response he got:
#161995 - Work it out! The exclamation mark implies either anger or shouting. The subject is implied. Only 3 words used Responding to: Sandeep Gupta's previous message Do the sums yourself, or use one of the ready-made calculators; eg, Basically, quit bugging me, don't be so lazy, figure it out yourself http://www.keil.com/c51/baudrate.asp ...and here's a link you can go read It's okay, Erik... I didn't expect you to understand this point, nor would I comment as to whether or not you were rude. Some things are just better left alone... Besides, your native language isn't English, right? I believe, though, that Andy Neil's is... For others, I might suggest the following: Remember back in college when you just finished learning double and triple integrals, when you came across this new set of equations? 
If you asked the instructor, "Excuse me, are the symbols the same kind of thing as a triple integral? I can't remember ever seeing these before", and the instructor looked back at you and said, "Work it out!...Do the work yourself, or you can go read this book" (in Russian, not English). You might get the impression, "Wow! What an asshole! I asked a simple question, and that dude snapped back at me... Either his wife just left him, or maybe he came out of the closet this morning, and all the guys at the gym won't hang out with him anymore...or maybe he's just a short, egotistical, pisser with control issues...who knows" This is suppose to be a teaching site (I thought), and if your posts are full of sarcastic crap, or insulting comments, keep them to yourself - leave them off the forum. If you got picked on a lot as a kid, you probably aren't the best teacher, and probably shouldn't try to compensate for this by being rude to others. If it's that you're just frustrated, because this question has been asked before, maybe you shouldn't respond either...Somebody else will. I'm pretty sure this subject has been talked to death here, it just seems odd it keeps happening. This is a bunch of utter nonsense. Using the second timer, one can, and it's no secret, use 12 MHz and, therefore, use 6 MHz to communicate with a PC. It may not be at a high baud rate, but it's possible. Anyone who has taken a few minutes to read the datasheet and given it a few milliseconds' though can see that. I seldom use the serial ports, and even less frequently use them with a PC. However, I've often used 11.98 MHz and 12.096 MHz, and, yes, even 6.048 MHz to generate a baud-rate-generator clock with other MCU's, so it certainly isn't impossible with the 805x. It's even possible to use the same timer one would use at 11.0592 MHz. Encouraging people to ask simple questions before doing the most elementary reading is like telling a child to ask a stranger whether it's OK to cross the street now, rather than looking for himself. First of all, the child will never learn how to do it properly, and, secondly, it's only a matter of time before he'll be misled. If exhorting the O/P to learn to do useful work rather than to beg makes me an asshole, then I can live with that. RE |
| Topic | Author | Date |
| Serial Communication using 6 MHz Crystal | 01/01/70 00:00 | |
| Work it out! | 01/01/70 00:00 | |
| Yes, it is possible | 01/01/70 00:00 | |
| Or been here too long | 01/01/70 00:00 | |
| ...being a long timer | 01/01/70 00:00 | |
| You are right ! Dave | 01/01/70 00:00 | |
| if you give a man a log | 01/01/70 00:00 | |
| totally befuddled... | 01/01/70 00:00 | |
| no quotes from above | 01/01/70 00:00 | |
I remember best... | 01/01/70 00:00 | |
| Horesfeathers! | 01/01/70 00:00 | |
| Case and point... | 01/01/70 00:00 |