"Craig E. Gooder" wrote: > I WANT TO DO RS232 FROM MY COMPUTER TO A PIC16C65 OR 74. LOOKING AT THE Craig, firstly, please, pretty please, don't use all capital letters in your messages - it is *very* hard to read. And you want your messages to be read, not ignored. Using all caps is considered to be SHOUTING. Ok, enough of netiquette - as to your questions; it would be easier to give advice if you gave more info as to your actual application, but a few points; the MAX-232 (I prefer the pin-equivalent MAX-202 because it requires smaller (0.1uF) capacitors) has two transmit and two receive buffers. You can use them for any purpose you like. Obviously you will use one each for TX and RX data, so you have two left you can use for hardware handshaking if you like. Since the 16C74 has no dedicated serial handshake pins, you would just select two port pins to use for RTS/CTS handshaking if you go that way. But depending on what you are actually doing, it may not be necessary to use hardware handshaking. If for example you are sending data to the PIC and expecting some kind of response before you send the next block, that will be sufficient handshaking. As long as there is enough buffer space for the maximum size data block, you won't have a problem. Note that the PIC will have no trouble receiving the data at any reasonable rate (i.e. whatever the PC can send it at) as long as you are not doing any substantial processing of each data byte on the fly. A microcontroller like the PIC can easily produce or consume data at 115200 baud, in short bursts (because of limited RAM for buffering). That's about all that can be said without more detailed information. Clyde -- Clyde Smith-Stubbs | HI-TECH Software, | Voice: +61 7 3300 5011 clyde@hitech.com.au | P.O. Box 103, Alderley, | Fax: +61 7 3300 5246 http://www.hitech.com.au | QLD, 4051, AUSTRALIA. | BBS: +61 7 3300 5235 ---------------------------------------------------------------------------- For info on the World's best C cross compilers for embedded systems, point your WWW browser at http://www.hitech.com.au, or email info@hitech.com.au