> Does anyone know of a change recently to the way 16C54-RC/P accepts
> programming? I used to buy these all the time and set the oscillator bit to
> XT and never had a problem but the last batch of 100 is causing me some
> problems.
>                                                        I shipped them to the
> assembler and he indicated that none of them seemed to work.  Had them sent
> back to me and they show that the device is set for LP as an oscillator
> type. Before I give up and say it's operator error I thought I'd ask the
> group if you knew of any change in the way things operate.
>
> The way I figure it ... in order of most likely to have occurred
>
> 1.  I goofed and hit the 'O' key and advance the Oscillator tyoe to LP
> 2.  My Parallax programmer let me down
> 3.  Microchip changed something and things don't work the same as they used
 to.

Hmm... are you code protecting the parts?  If so, have you always done so?
I don't know what a 16C5X reads out of protected parts these days; my
recollection is that that the status register reads "scrambled" but that
the top 8 bits are normally all zero so that wouldn't matter.  If Mchip added
some feature to the new silicon which uses bit 4, that could cause a protect-
ed chip to LOOK like it was set for LP mode.

As for failure to operate, if you've confirmed that the clock is indeed not
running, then it would appear that either:

[1] The parts really have gotten mis-programmed to LC mode.

[2] You got a batch of bad crystals/resonators (did you buy those in a batch
    with the PICs?)

[3] "You get what you pay for": you bought chips which were not specified
    as having useable oscillator circuits (an RC OTP would only be tested
    with RC oscillator mode; while most will work if programmed for XT or
    LP mode, this is not guaranteed.  In fact, it's possible (though IMHO
    not terribly likely) that Microchip found it had a wafer full of parts
    which passed all the tests EXCEPT the XT oscillator test and decided to
    package and sell this batch as RC parts.

Without further information, I can't say whether #1, #2, or #3 is the cul-
prit, but you may want to consider all those options.