Looking at the datasheet, that would appear to be the right thing to do (though freakishly, their example circuit shows the pin tied low which looks rather counterproductive)... definitely a better option than swapping the IC, though it's rather strange that units appear to degrade over time.
That PDOWN pin ought to have been labeled as a RESET pin, since that's how it really behaves for all practical purposes.
Yeah, I wonder if it's the internal power-on-reset circuitry of the chip itself that goes bad over time. But why, yes.. why.
It doesn't look like this should affect the IDE bus though, which is one of the other symptoms that people see when the 4231 is playing up. Anyone got a unit that's unwell and both the 4231 and the IDE drives don't respond that they can try this on?
When that happens, I'm not so sure that the problem is really (or only) with the 4231 chip. Basically, if *anything* goes wrong on that bus, then the ethernet, USB, 4231, and IDE can all suffer, and it's not completely clear which ones are actually bad.
We've had quite a few instances of this where it turned out to be a particular data pin (D5
) of the ethernet chip that gets stuck (low
But, yes, it would be useful to hear if there are still any unfixed units out there with IDE problems that have been attributed to the 4231..
I suppose one possibility there, could be that the semi-initialized 4231 chip could have just gotten into a weird state where it's driving one or more data pins permanently until it gets a proper reset.