Capture and compare serial data

[mackrackit]

Not sure exactly what you are trying to do?

Send the same thing four times and if any of them fail the whole thing fails? Even if one is good?

Even doing a compare will not tell you which one is good. Only the checksum (CRC) thing will do that.

[Dennis]

Hi Dave

Send same thing 4 times
so
1
2
3
4
and compare instance 3 and 4 'cos usually correction occurs on 1 and 2
If 3 and 4 match then TX was good.

Hope that helps

Kind regards
Dennis

[mackrackit]

OK, how about this.

Receive the first two and do nothing with that data because it is most likely bad.

Do the checksum on data #3.
if good then ... STOP??
OR go on and run the check on data #4

If #4 check then GO ON.

No compare any where...

MAYBE...

[Dennis]

@ Dave

OK cool

So I Will
1. Capture all 4 lines into and array each one is 4 bytes and a checksum byte so array needs to receive 20 bytes total.
2. Check 4 for checksum match
Continue on ...

It certainly seems doable and will give it a bash right away!

Still just wondering if there is a way to capture and compare all 4 lines

Kind regards
Dennis

[mackrackit]

If you really want to do each line then I guess the way would be ...

IF array1 bit1 = array2 bit1 then
IF array1 bit2 = array2 bit2 then
IF array1 bit3 = array2 bit3 then
......on and on and on....

But something like Charles said
IF check1 = check2 then
IF check2 = check3 then
IF check3 = check4 then
Hey. it is done...

[Charles Linquis]

Depending on what your data looks like, you can also do some neat things with:

ARRAYREAD (name_of_first_string),(nocompare_location),(numbe r_of_chars_to_compare),[WAITSTR name_of_second_string]

[Dennis]

AHA...

That's where I'm stuck ....at step 1 I mentioned earlier ...

1. Capture all 4 lines into and array each one is 4 bytes and a checksum byte so array needs to receive 20 bytes total.

I this is the line I am using to receive the data

DEBUGIN [WAIT(SYNK),WNUM,XNUM,YNUM,ZNUM,CHECKSUM]
           ' wait for SYNK, when received store next 4 bytes in variables WNUM,XNUM,YNUM,ZNUM
           'then send these to hyperterminal or serial program or wherever

What must be changed in order for me receive it 4 times and build the array?

I was playing around with this as a start..but it's here where I am stuck!

For counter=0 To 19 
DEBUGIN [WAIT(SYNK),WNUM,XNUM,YNUM,ZNUM,CHECKSUM]
           ' wait for SYNK, when received store next 4 bytes in variables WNUM,XNUM,YNUM,ZNUM
           'then send these to hyperterminal or serial program or wherever 
         counter=counter+1
        Next

As always any help would be appreciated

Kind regards

Dennis

[aratti]

Hi Denis, I think you could take some advantage from this thread :http://www.picbasic.co.uk/forum/showthread.php?t=12870
In post # 4 DT is giving an interesting snippet for having 2d array in PBP.

I don't know if you have already used bi-dimensional arrays, if not let me say that they could easy your compare problem.


You cannot corrupt the variable within a FOR/NEXT cycle:

For Counter =0 to 19
.
.
.
counter=counter+1
Next Counter

You should expect some problem from this code!

Al.