help about receive on RS232

[mojsa2000]

Hi
I have a question about RS232 communication. I use the #RDA_int and when
I receive a character (for example 'd') on this port I send an answer to
sender(PC) and wait to receive next byte. But PC needs to send 2 bytes because
first byte be ignored. Now I want to ask why this takes place?
I want to send a INT16 and a INT8 from PC to PIC and make this protocol.

This is my program. Also I use a PIC16f877a.

[SherpaDoug]

When you use a line like

buffer[0]=getc();

the getc() consumes the character in the buffer and another getc() won't get the same character but must wait for the next one to be received.

So if you have

if(getc()=='d')

followed by

if(getc()=='s')

you are comparing the FIRST character received to 'd' and the SECOND character received to 's'. If there is no second character yet the getc() function will wait all day for one to arrive.

I assume you really want something like:

buffer[0]=getc();

if(buffer[0] == 'd')

if(buffer[0] == 's')
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[mojsa2000]

Dear SherpaDoug
You're right. Thanks alot. I used your idea and my fault fixed.

best wishes