You're doing strings of ifs again - where a case would be a far more obvious candidate



Why are you putting the entire code within while(RI) ?

You need to:

1. wait for a character;

2. when one becomes available, read it;

3a. if that completes a message, handle the message;
3b. if it doesn't complete a message, repeat from (1);

4. repeat as necessary.

Which is the converse of transmitting, as outlined previously: http://www.8052.com/forum/read/169121

Why are you back to polling? I thought you wanted to use interrupt-driven IO?

You should avoid the use of "magic numbers"; eg,

if(c==0x053 || c==0x056) //If S or V entered, store as 1st character

If you're specifically intending these values as characters, then write them as characters - not as "magic numbers"; eg,

if( c=='S' || c=='V' ) // If S or V received, store as 1st character

Also, consider the use of arrays - instead of lots of individual variables...