Capture and compare serial data

[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.

[Dennis]

@ Charles ..thanks a million for the tips will check them out as soon as I have the array(s) built up.

@ Al .. Thanks for the tip there , has me wondering how I can put the 2D array to use for my a solution.

I am guessing as a start I should replace the DEBUG sommand with something like serin2 and build the array with one command ?
Something like :

SerIn2 GPIO.4,T2400,500, main,[WAIT(SYNK),STR DATAIN\4]

This would indeed create an array and store the 4 bytes and the checksum byte.
But again I want to to do this 4 times and have either one array with the contents of each time OR I could try have 4 different arrays (one created for each time) and then check the checksum values for each array.

Now I am wondering if I am doing the right thing , perhaps I should rather have more SYNK/qualifier bytes and send and receive one instance of the data and checksum that.
Problem is that sometimes some corruption occurs at the receiver side so to solve this I thought it best to send more instances of the same data.

Any more suggestions are welcome

Kind regards

Dennis