If you are using PIC BASIC PRO (or PIC BASIC) it is very easy to set up. Check the manual for the command Serin. It has the following form:
SERIN Pin,Mode,{Timeout,Label,}{[Qual...],}{Item...}
So if you want to use PortB.0 all you do is
Serin 0, 6, MYVAR.
That will put the into MYVAR the value transmited. So if you transmit an
"A" from the PC, MYVAR will have a binary 1000001 (or dec 65). if you want to receive more that one character, then you can add MYVAR2 after MYVAR to allocate space on that variable, and so on.
I believe you are a little bit confused with the whole transmitting stuff serially.
In a nutshell, serial transmition can be done asynchronous or synchronous, all that means is wheather or not you supply a clock. Since you are talking to the PC you normally use asynchronous (no clock siganl supplied). The Serin command handles asynchronous transmitions only.
Asynchronous transmitions have a format or "protocol", to understand better you need to do some research, but the protocol is that when a transmitions begins the first serial bit sent is a START bit. Then it sends a Parity bit (some error checking), then the DATA is sent. The data consists of only 8-bits, so you can only send numbers from 0-255 or in other words binary 11111111., then the last thing sent is a STOP bit. So
[START]-[PARITY]-[DATA]-[STOP] is the packet sent serially each time.
Since the DATA is 8-bits, that is where the ASCII enters. ASCII stands for American Standard Code for Information Interchange. IT is just a STANDARD that everyone has agreed on and so that you know if you receive a decimal 65 (which is the same as binary 1000001, hex 41) you can interpret it as an A (not lower case a). Do you have to interpret it as an A? No if you don't want to, but you know that if you use hyperterminal and you type an A, you know that your pic will receive a
dec 65. The ASCII codes go from decimal 0 (NULL) to decimal 255(empty). Check
https://www.asciitable.com for all the values. Can you guess why do they go to 255 only?
So after all these my point is that it doesn't matter what the PC sends, is what you interpret it to be. ASCII are binary numbers with a meaning, but they are still binary numbers and you can give them any meaning. So if you want the PIC to start the Cold fusion machine when it receives binary 1000001 from a PC, then you make sure that the PC sends an "A" but when you receive it make sure that you check you received binary 1000001, which at the end is the same thing, just a standard :lol:
Ivancho