I also advise you to use a Pic with build in serial. And if you do not want to change the Pic for now because you have code snippets for 16F84, then I tell you you have nothing to worry about. The PIC16F628 is (you may see it like) an improved version of the old 16F84. It has built in USART and 4 comparators, CCP, PWM a 16bit timer, and it can be really easy configured to act like the good but old from now 16F84. If you cannot manage to configure it a lot of people here (including me) can offer you the code. And YES use MAX232. I never had a problem with it. My best regards, Sascha -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of tim_webb@agilent.com Sent: Friday, October 15, 2004 8:07 PM To: piclist@mit.edu Subject: RE: [pic]-Interface pic16f84a with rs232 I strongly encourage you to use the MAX 232... or even simpler the MAX 233 less components required and you can also request free samples from the manufacturer. I have tested both parts in designs and they both have performed flawlessly for all of my projects. I also suggest that you ditch the 16f84 for a Pic with a built in serial USART, it will make your life so much easier. You can even request free samples from Microchip too. I believe learning is not about using old technology and bit banging, it is about learning how to utilize the newest technology at you disposal, it's quicker, it's easier, and its a lot more forward compatible as your project evolves. Don't waste your time with old technology, move forward and use components that are not or will not be discontinued soon. In an R&D environment where I work, we are actively looking for the newest technology to push the envelope, using Obsolete components may leave you in a position where you will have to do a complete redesign then the obsolete parts are no longer available this is time consuming and not forward thinking. If you are anything like me, I'd rather do the right thing the first time, rather than have to redesigning a failed design later, I have better thing! s to do, like search for newer technology for my next project, rather then do something over that should have been done right the first time. Always do you research before you start a project, it pays off in the long run, you become a leader in the newest technologies available, before you know it others will come to you for advice, and you become a successful circuit designer. And last but not least, this Pic list is one of the most resourceful places to get quick suggestions, pro and cons, and good advice. Good luck Tim EE/Embedded solutions Developer and Designer -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf Of Byron A Jeff Sent: Friday, October 15, 2004 7:59 AM To: Microcontroller discussion list - Public. Subject: Re: [pic]-Interface pic16f84a with rs232 On Fri, Oct 15, 2004 at 01:12:47PM +1000, Mr.Pink bedak wrote: > Hi... > Im working on with my project and got stuck.i want my > output from pic16f84a to be feed to Computer using > rs232. Here's my obligatory 16F84 is obsolete comment... The 16F84A is obsolete. Check the archives for arguments for and against. I have a webpage that talks about why you should move up to newer parts featuring the 16F88: http://www.finitesite.com/d3jsys/16F88.html > I have already check the internet about that > and stiil confuse.Some of solution says > -1-that in order to interface pic16f84a with rs232 > MUST have MAX 232 That's not completely true. > -2-there is no need of MAX232. That's not completely true either. > > Problem -How can i interface pic16f84a with com via > rs232. By understanding that there are tradeoffs in the two approaches. RS232 (actually EIA232) specifies electrical characteristics for the interface. However most hardware especially PC hardware is much more forgiving. The spec says max of +/- 25V, min +/- 3 volts with the space between -3V and 3V as undefined. However most PC serial ports are quite happy receiving a 0V, 5V signal even though it's out of spec. But in the end you have other worries. So use the MAX232 which guarantees a +/- 10V signal which is RS-232 spec. That way you're assured that it'll work in every situation. However if you wish to be say.... frugal, there are other out of spec interfaces that you can utilize. Two examples off the top of my head are Dale Botkin's two transistor interface here: http://www.botkin.org/dale/rs232_interface.htm And Wouter's El-Cheapo interface for his Wloader system: http://www.voti.nl/wloader Note that on Wouter's page he points out that while the MAX232 works reliably in almost all situations, that the El-Cheapo often had problems. Which illutrates the point. > thanks No problem. BAJ _______________________________________________ http://www.piclist.com View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist _______________________________________________ http://www.piclist.com View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist __________ NOD32 1.895 (20041014) Information __________ This message was checked by NOD32 antivirus system. http://www.nod32.com _______________________________________________ http://www.piclist.com View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist