Filtering DFCO Cells

[Blacky]

EFILive provides the same set of operators as 'C'. (Except for equality in C is ==, in EFIlive it is just = and non-equality in C is !=, in EFILive it is <>). And there is no ?: operator, use the built in function iff() instead.

So create a calcualted PID that returns 0 or 1:
iff({GM.STATE05} & 128,1,0)

Then use that calculated PID in the filter.

Regards
Paul

[Tordne]

EFILive provides the same set of operators as 'C'. (Except for equality in C is ==, in EFIlive it is just = and non-equality in C is !=, in EFILive it is <>). And there is no ?: operator, use the built in function iff() instead.

So create a calcualted PID that returns 0 or 1:
iff({GM.STATE05} & 128,1,0)

Then use that calculated PID in the filter.

Regards
Paul

Thanks mate!!

What is the 128, is that a position marker or something for the binary data? It looks like the DFCO portion of the STATE05 PID is going to be in the first position.

Cheers,

[Blacky]

The bits are listed MSb to LSb (Most Significant bit to Least Significant bit). 128 is the equivalent of 10000000 in binary. It is used to isolate just the DFCO bit in STATE05 that we are interested in.

The & operator will take the value of STATE05, AND it with 10000000 to get a zero or non zero result based on the value of the 7th (MSb) bit.
i.e. if the DFCO bit was set in STATE05 then the value would be 1xxxxxxx, if DFCO was not set then the value would be 0xxxxxxx where the x's are don't care values (i.e. all the other bits in the STATE05 value).

Doing a bitwise AND:
1xxxxxxx
&
10000000
is
10000000
Which is non zero and evaluates to TRUE in the iff() function.

0xxxxxxx
&
10000000
is
00000000
Which is zero and evaluates to FALSE in the iff() function.

Hope that helps.

Paul

[Tordne]

Great explanation Paul . I knew it was going to be something like that, I just wanted to make sure of the logic so that I could isolate the correct bit for DFCO.

Cheers,

[joecar]

Do the other C bitwise operators like >> and << work...?

If I wanted to plot GM.STATE05 bit 7 on a chart,
would I create and plot a calculated pid like either of these:
{GM.STATE05} >> 7 & 1
{GM.STATE05} / 128 & 1



P.S. What is the order of precedence of the operators in EFILive...?

[Tordne]

So create a calcualted PID that returns 0 or 1:
iff({GM.STATE05} & 128,1,0)

Then use that calculated PID in the filter.

Hi Joe,

I think this is what the PID might look like, using the DFCO state as an example.

[Blacky]

I have not implemented >> and << (I guess I should, it would not be difficult).

Use the iff() function and & operator described previously to plot individual bits as either 0 or 1 on the charts.

See attached image of new page just added to the Scan Tool manual.

Paul

[joecar]

I think this is what the PID might look like, using the DFCO state as an example.

Use the iff() function and & operator described previously to plot individual bits as either 0 or 1 on the charts.

Andrew,
Paul,

Hi there; I didn't think about it, but you're right, that would produce the required plot.

Thanks.

[joecar]

See attached image of new page just added to the Scan Tool manual.

Thanks, I'm going to print it out and paste it to the inside of my glovebox door...
(programmers always print out precedence charts).

Joe

[Tordne]

Thanks, I'm going to print it out and paste it to the inside of my glovebox door...
(programmers always print out precedence charts).

Joe

LOL... You guys are scaring me again

You'll be able to ask yourself when you come to a T junction "should I turn left | right?"