Serial Communication Problem

[elec_mech]

Okay, I brought this home, tweaked it with a different programmer and when I try to compile it, it says it is unable to "fit variables". I'm think this will work as it stands, but you may find some errors on my part.

In any event, this waits for serial data and once received looks at the first two characters to be sure the string is what you expect it to be. You can take this out if your serial input changes every time (the first two and last two characters in a string). If you ever expect more than 40 bytes on a single serial string be sure to change that in the variable definitions.

The branch command really comes in handy for looking at a single character at a specific location in the string and doing different things instead of using the if command.

Take a look at this and see if it helps. Feel free to ask questions.

-Tony

[elec_mech]

ASII Table - All important to serial comms - Check this out:
http://www.lookuptables.com/

[leemin]

ok. thanks for you all previous help. i can work with the USART interrupt with my code already but now i encounter with a new problem.
im using 16f877a.
i need to receive a string of command from computer. then execute some function after received a valid command. now i need to execute the blinking effect by toggling the enable pin to let the led on and off continuosly untill another set string of command come in and either stop blinking or continue blinking.
but now i found out that the blinking sub-routine is a dead loop. when i continuosly execute the blink function and a new string command come in from computer my firmware will hang there.
any solution for this?
i need you all suggestion.
thanks

[BobK]

Hi Leemin,

It's a great idea to have the micro do as much as possible but sometimes it's necessary to have external hardware do some work to free up the micro to do other things more important. Add a gated pulsing circuit that you only need the micro to turn on and off. This can be a single chip circuit like using a CD4093 or even a CD4060. A CD4060 lets you choose flash rates juct by selecting the appropriate output. These are simple circuits and only require a few discretes to finish the job. Let the micro do the more serious stuff.

BobK