Hi Sean,
Yes its got me too. I havn't used these devices either and was only
using-them-up in this simple application as I had a couple laying around
with a '57 as well. At this point nothing but clock,reset, 5v and ground are
connected to this device. The XTAL has worked elsewhere and the same PCB is
now powering a PIC16C84 that is working fine. I just don't know what it is
and have spent conciderable hours looking at this problem. It may well be
just some lines in the initialization of the device, but then I wiould have
expected MPLAB to pick up the fatal ones. Ideas?

-----Original Message-----
From: Sean Breheny [mailto:shb7@CORNELL.EDU]
Sent: Monday, 8 May 2000 10:46
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: ?? Short ??


John,

I don't understand. They program OK but draw tons of current when you put
them in a normal circuit, regardless of whether or not they are in reset?
If they program OK, it can't be a simple short of power/GND since they
require power and GND to program, do they not? (Never have used the the
16C55 or 57)

Sean

At 10:36 AM 5/8/00 +1000, you wrote:
>Hi Tony,
>All I/O is accounted for and power supply is OK, nothing going into OCS2
but
>XTAL. They both programmed and veryfied OK.
>
>-----Original Message-----
>From: Tony Nixon [mailto:Tony.Nixon@ENG.MONASH.EDU.AU]
>Sent: Monday, 8 May 2000 10:20
>To: PICLIST@MITVMA.MIT.EDU
>Subject: Re: ?? Short ??
>
>
>John Orhan wrote:
>>
>> Hi Tony and thanks for your resopnse,
>> I/O that is not used is floating, only porta is configured as an output
>port
>> to toggle A0 on and off. The fault exists in reset state. Any ideas? I
>guess
>> I would throw them out if I was sure that I had done everything correctly
>> and they still did'nt work. Chip is in the right way ( I made sure of
that
>> one from the start). Please advise.
>
>I would've make all unused pins outputs and make sure they are not
>connected to anything. Floating inputs cause problems.
>
>If the fault exists only when the chip is inserted, check that 5 VOLTS
>is on pin 2 and GND is on pin 4. Make sure no voltage is connected to
>OSC2.
>
>If this checks out and the chips are inserted correctly, I would assume
>they are faulty.
>
>Did they program and verify OK?
>
>--
>Best regards
>
>Tony
>
>http://www.picnpoke.com
>mailto:sales@picnpoke.com
>
|
| Sean Breheny
| Amateur Radio Callsign: KA3YXM
| Electrical Engineering Student
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