>Developement EPROM chip :   PIC16C55/JW-S1
>Final OTP chip          :   PIC16C55-XT/P
>
>Clocking method         :   8MHz Crystal
>
>I tried to program the OTP to use an HS clock. But it reported that
>it had been programmed LP !
>
>Is there something I don't know about these OTP chips. I thought they
>are supposed to be able to do everything the EPROM devices are.
>
>Could it simply be that this OTP chip is defective ?

No your OTP is Ok.

You just cant reprogram an -XT OTP device to HS mode.

OTP devices (5X series without a letter A at the end) have
the OSC config bits in fuseword pre-programmed.

XT device has ..01 as low bits in fuseword. An attempt of
overprogramming to HS ..10 in low bits will get the both OSC
config bits to 0, which will be LP, and that what you did get.

You have to use -HS parts or 16C5XA parts if they are available.

You may buy RC parts (cheap) and try them, they will get programmed
as HS. However they may not work in HS. Well as known to us some
companies are doing that. Using RC parts in HS mode.

FYI Basic Stamp II has 16C57-RC running at 20Mhz, those in HS mode.

antti
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-- Antti Lukats                          Silicon Studio --
-- sis@rasi.lr.ttu.ee                    PO Box 3500    --
-- ftp://rasi.lr.ttu.ee/pub/sis          Tallinn EE0001 --
-- http://rasi.lr.ttu.ee/~sis            Estonia        --
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