On Mon, 26 Jun 2000 14:38:29 +1200, you wrote:

>I just received this comment from Alice on operating PICs at low =
voltage.
>Interesting to note MChips comment on what is presumably not a datasheet
>spec ? and Alice's experience.
>This parallels my experience with the 16F84 (sample of 2 or 3 only) at =
low
>(below spec) voltage.
>
>Note the comment re low volrtage operation of MChip versus NatSemi =
eeproms.
>
>RM
>
>++++++++++++++++++++++++++++++++++++++
>
>>Im writing to you from home because of major email troubles at work.  I
>>recently went to the Mchp seminar.  The presenters said that most of =
the
>>newer parts will work down to 2.2 volts.  My own experience with a
>>datalogger (the al-o-tron Mark 1 landfill logger):  It was out in Claif
>>outback for a week, in temperatures ranging from 20 C to 45 C, and when=
 i
>>retrieved it the 9-V battery was down to 3 V.  I had a seiko LDO 5V
>>regulator in it, but no brownout or lobattery circuit. (ignorance is
>>bliss, let me tell you...)  It was reading about once an hour, and as =
far
>>as i could tell did not lose any eeprom data.  It had an external =
eeprom,
>>a 93lc66 i think.  One thing, the nat semi 93lc56/66 chips are a LOT =
less
>>fussy than the MCHIP ones.  The MCHIP ones tend to crap out anywhere
>>below 4.9 volts. =20
I think this is an intentional undervoltage write-lockout feature, MCT
do different grades of chip (LC, AA ) for different voltage ranges.=20