read RS232 more than one time?

[ahmad-al3omar]

hi;
i am using RFID reader that send the ID by RS232.
i used PIC18F458 and 4MHz crystal to read this data, and then compare it with saved one, the program works perfectly on the simulation but on real time the program work for one time only( the program still running but the PIC read one time only from the reader) can you help me to finde how can i read more than one time ??
thank you
my code

[Humberto]

The problem is in the interrupt handler code.
Receiving data at @9600 bauds implies that one char is arrieving every 1.04 ms, hence
it is not a good practice to write the LCD after received every char. Take out the printf(LCD)
function of the interrupt and put it in the main().

1)The clue is, inside the interrupt store only the received chars and detect the End of String
character. Then -in main- use the printf(LCD) function to show the received data in the display.

2)Add ERRORS in the #use rs232(........, ERRORS) directive.


Humberto

[Ttelmah]

First,add 'ERRORS' to your #use RS232 line.
Second add a limit check to 'i' in the interrupt.
Now, tell us what the port E lines 'do'?. Also how frequently the device sends the ID?.
Once you see the ID, you are toggling various line combinations, and pausing for half a second before looping back to try again. If the ID comes more often than once evey half second, the code may have received more than one ID in this time. The buffer will then have overflowed, and data will have been lost. If the wanted ID is found, you reset 'i' immediately, while if the ID is not one of the tested ones, i is not reset till after half a second. In the second case, if even five characters arrive in half a second, there will be an overflow...

Best Wishes

[ahmad-al3omar]