View Full Version : Question to Tap your expirence
03-27-2009, 09:30 PM
I've worked with allot of processors over the years. Mostly but not entirely on the intel side. Starting with the 6502's, working through that into Z-80's, the 8080's,·8085's·and 5 digit variants of those, and the Atmel processors. Looking at my stack of fried props, it seems to me like the prop is a little more fragile than other processors I've worked with. I just don't remember feeling like my development efforts in the past required such a backstock of fresh chips. I don't want to take away from the capabilities and innovation of the chip but this issue·has been·bothering me a bit.
I have allot of respect for the population of this forum. What's the collective opinion?
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03-27-2009, 09:36 PM
For some strange reason, despite my "butter knife into the socket" approach that I take
to trying things with the Propeller, I haven't managed to fry one yet. Granted, I'm observing
rules regarding power input and I/O, but I don't have any reservations in regard to testing
conditions outside the box just to see what happens.
The Propeller appears very robust from this angle.
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03-27-2009, 09:41 PM
I have a DYS board with just a prop, crystal, EEPROM and MAX2323 and some DYS extensionboards
I did a lot of testing with this boards combined with breadboards.
And I have a PPDB and these are the only TWO props that I have and both are still working properly for two years now.
So I got the impression you seem to have habits while developing where you give the chips a quite great amount of EMV and other stress
03-27-2009, 11:58 PM
Hi everyone , I've got a ppdb, demo board and a home made breadboard prop and done somethings 'accidentaly' to them and thought for sure they were gonner's but they took a licken and kept on tickenn !
Fix it, if it ain't broke·
Dave Ratcliff· N6YEE
Phil Pilgrim (PhiPi)
03-28-2009, 12:05 AM
I've found the Props to be quite robust. I've used more than a dozen of them in various incarnations, some of which have suffered grievous soldering errors, bus conflicts, etc. None has failed.
03-28-2009, 12:10 AM
I too have found the prop to be very robust, I been that confident with them that I haven't even been static safe, touching a grounded pc case before manually picking up the prop etc, and I've not fried one at all.
http://www.propgfx.co.uk/forum/·home of the PropGFX Lite
I do have to agree... If anyone's prop should have failed, it should be mine... The other day I wasn't thinking and hooked the com port of a computer directly to the pins of the stamp with no level correction. I was sure I smoked it, or at least the two pins I was connected to... I was shocked that it still worked for me, never had one fail yet...
I've not had any problems with them on my home-made PCBs, and don't take any precautions when inserting and removing chips from their sockets. Most problems are probably caused by people not connecting both supply pins - I always connect both of them and decouple each pair. Some people use solderless breadboards, which are notoriously unreliable and could cause chip failures due to poor connections.
I've also got a Proto board and haven't had any problems with that. There has been the occasional chip failure with them, but I get the
impression that they are very reliable.
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Post Edited (Leon) : 3/27/2009 5:39:44 PM GMT
03-28-2009, 12:57 AM
The "PLL failed" tales are somewhat frightening as no one seems to be entirely sure what causes the problem but they seem to be rare occurances and I've read very few reports of that or any other failures on this forums.
I discount tales of woe along the lines of, "my chip evaporated leaving nothing behind except its legs in the socket when I connected a car battery to its power pins", because that's the sort of thing which is likely to happen with any chip http://forums.parallax.com/images/smilies/smile.gif
I haven't used Propellers frequently enough to become blasé about juggling them next to Van der Graaf Generators but I haven't seen anything which suggests I need to be more cautious than I would with other processors. In some respects ( outputs and short-term higher currents ) it appears they may be more robust than others.
The PLL failures seem to be caused by people thinking that they only need to connect one supply pin.
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
03-28-2009, 02:44 AM
I have had 3 fail on me so far.
1 i accidentally connected 12V to the power pin.
1 for some reason started giving low only on 10 of the pins. The same 10 i was using to run 4x16 decoders with at high speeds. no clue why that failed.
1 i soldered on backwards and it broke while trying to desolder. Not really a failure but it isn't working.
All being the small QFP type.
I don't blame parallax for any of them. 2 are definitely my fault and I probably abused the middle one some how.
Need to make your prop design easier or secure? Get a PropMod (http://propmodule.com) has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
03-28-2009, 02:52 AM
On my first attempt to get going on the Prop path, I picked up the wrong psu. This one had been modified to be the reverse polarity so the one and only prop I had was subjected to 3.3v reversed and only limited to about an amp or so. A sick feeling was quickly cured when to my total disbeleif the thing hadn't been toasted. It is still my main experimental toy (in a version of the prototype board).
The thing must be bomb proof! ( he says holding all things crossed )
03-28-2009, 03:11 AM
One of my props lost PLL function in an over-current situation. Funny thing is prop was just mostly an innocent bystander i think ... a prop pin was connected to a motor controller input and the motor connected had hit a bind so that no amount of current would have made the shaft turn. Oh well at least I learned soon after that the prop can run at 20MHz without an external crystal :)
Propalyzer: Propeller PC Logic Analyzer (http://www.brouhaha.com/~sdenson/Propalyzer)
03-29-2009, 04:27 AM
The chip I tormented was a 40 pin DIP, do different packages with differing power feed pin layouts suffer more than others?