Oh, by MCC I mean MPLAB Code Configurator, the plug-in for MPLAB X that hel=
ps=20
(despite this kind of issue) with setting up a project from scratch and pro=
viding=20
standard libraries.

On 7 Mar 2019 at 18:49, Harold Hallikainen wrote:

> Strange! Doesn't MMC use SPI, not I2C? I agree that it LOOKS like the
> semicolon would terminate the while, and the stuff after that is just
> a block that always runs. I've used the Microchip MMC code on a
> non-interrupt basis without issue.=20
>=20
> Good luck!
>=20
> Harold
>=20
> > Hi list,
> >
> > I've been looking for the cause of an occasional software hang-up.
> Happens
> > very
> > rarely in practice, but have found I can re-produce it at will by
> shorting
> > I2C line(s) to
> > GND. This supports the observation that the problem has only
> exhibited
> > while I was
> > physically handling a PCB ~ so probably an ESD transient
> corrupting I2C
> > transfer.
> >
> > If it does ever happen in the field it wouldn't be great ~ it's a
> battery
> > powered device
> > with an LED (that the user probably can't see) that stays on
> causing
> > considerable
> > current draw when the problem manifests, with no way of resetting
> without
> > removing
> > the batteries which requires tools. I'd like to the make the
> program
> > recover from this
> > auto-magically.
> >
> > I went looking though the I2C code looking for places it could
> hang, e.g.
> > while
> > statements. The following section of MCC generated code stands out
> as odd,
> > within
> > the function I2C1_MasterTRBInsert()...
> >
> >     // for interrupt based
> >     if (*pflag =3D=3D I2C1_MESSAGE_PENDING)
> >     {
> >         while(i2c1_state !=3D S_MASTER_IDLE);
> >         {
> >             // force the task to run since we know that the queue
> has
> >             // something that needs to be sent
> >             PIR1bits.SSP1IF =3D true;
> >         }
> >     }   // block until request is complete
> >
> > The semi-colon after the while() terminates the while statement
> (if I'm
> > not mistaken).
> > That's strange, as the braces that follow, and comments, suggest
> the line
> > PIR1bits.SSP1IF =3D true was intended to be inside the while loop.
> As it
> > would be if
> > the semi-colon wasn't there, so perhaps it could be a simple
> typo.
> >
> > I've updated MPLAB IDE X and MCC to latest versions, but generated
> code
> > remains identical to above.
> >
> > Tried removing the semi-colon alone, program doesn't function
> properly at
> > all. So if
> > the semi-colon was a typo, then it is just fortuitous that the
> code works
> > better with it
> > than without it.
> >
> > Tried removing the semi-colon and added an extra PIR1bits.SSP1IF =3D
> true;
> > after
> > the while loop (closer to the what the code with the supposed typo
> would
> > do), and it
> > seems to work better now. The I2C now works normally, still
> crashes with
> > stimulus
> > as described previously but now in a way that no longer causes it
> to hang
> > at this
> > point. That's good - I can now work on making it recover fully
> from such a
> > glitch.
> >
> > I'm not fluent in I2C, so hard to believe I might have found
> misbehaving
> > code in the
> > MCC routines. I could and probably should use the WDT to recover
> from this
> > and/or
> > other errors in a brute force kind of way, just have avoided using
> WDT so
> > far as
> > device is battery powered and WDT would increase power consumption
> ~
> > though
> > I'm using a PIC18LF46K22 and believe I can turn the WDT off during
> sleep.
> >
> > After sharing all this I feel more confident about solving the
> problem,
> > but still
> > appreciate comments, thanks for listening~!
> >
> > Brent.
> >
> > --
> > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist
> >
>=20
>=20
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> Not sent from an iPhone.
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