Dallas CRC8 Routines

[Tom Estes]

I'm not a VB person, don't even own a copy to try your routine.

The routines I wrote were for the Dallas Semiconductor CRC8 check. Any other CRC routine may not work in the same manner. I note you changed the table entries which may be in a effort to fix this but that may not always work either. Some CRC routines calculate with a different poly or "reflected" or changed in other ways. You will need to find out the particulars of the CRC your device is sending.

If you are trying to emulate the Dallas 1wire CRC8 then the table values you have are incorrect.

[CocaColaKid]

Tom,

I finally have everything working properly. Thank you so very much for your help and understanding.

[taats]

after a couple of hours of hard work, i got it working now...

so thanks anyway!!,

Taats

[CocaColaKid]

Is there an easier way to do this?

owin portb.7,0,[data_in[0], data_in[1], data_in[2], data_in[3], data_in[4], data_in[5], data_in[6], data_in[7], data_in[8]]

[Tom Estes]

Using other 1wire devices I have been able to do the following:

' Read the next 32 bytes, calculate running CRC but discard the bytes
For Index = 1 to 32
OWIn OWPort, 0, [CRCData]
GoSub CRC
Next Index
OWIn OWPort,0,[DesiredData]
CRCData = DesiredData
GoSub CRC

In other words there may be enough time in between data bytes sent from the 1 wire device to calculate the CRC on a running basis. If you don't need all the data the CRC can be calculated and the data discarded, retaining only that data you need.

[CocaColaKid]

I was wondering if that would actually work or not. This is my final line. Again thanks for all your help.

    for x = 0 to 8
    owin portb.7,0,[i]
    dq[x] = i
    next x