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1
Test Equipment / Re: HP 165xx analyzer cards threshold level
« Last post by BloodyCactus on Today at 01:23:35 AM »
there are dissasemblers 'inverse assemblers' around to display the decoded streams.
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Projects, Designs, and Technical Stuff / Re: cooktop lighting suggestions
« Last post by KM4FER on Today at 01:21:10 AM »

WOW !!!   I hadn't realized there were so many LED options available in automotive bulbs. 

Now a couple of those multi-LED units combined with some of the nice shiny stainless steel sheet I have as reflector and I think I'll be set.

Thanks everybody.

earl...
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General Chat / Re: What's your main operating system? (Poll)
« Last post by EdoNork on Today at 01:17:18 AM »
Total Commander alternative: FreeCommander.
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Beginners / Re: AC Zero crossing detect, H11AA1 troubleshooting
« Last post by wraper on Today at 01:14:01 AM »
No way this circuit could trip RCD unless you counting optocoupler pin numbers incorrectly. Therefore likely there is a leak somewhere else outside this circuit or you do not understand what you are doing. What happens if you disconnect one lead of 47k resistor? Does RCD still trip? Maybe stupid question, but is it really neutral? Don't you connect your circuit between Line and Earth by chance?
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connect the LED's in parallel but in opposing directions across 2 dio pins. Then to turn one led on, drive one pin high and the other low. To switch the other one on drive the pins the opposite way. Hope you can figure out what i'm going on about from that!

There is no combination that would allow both leds to be on at the same time.
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Just to explain the possibility of a fault even with two output pins pulled to ground : the SSRs can open with very little current. Currently they are driven with 10mA each, as per datasheet (AQZ205), but even 0.5mA I believe can cause problems.

Therefore even with two output pins pulled to the ground by say 10K resistors, if the middle pin goes open circuit and the top pin goes live, then both SSRs will come on, they will basically ignore the pulldown resistors.

The only way for this to work is to make the pull down resistors so small, so as to steal all the current from the SSRs, but they will do this continuously, not only during the fault descrived above, but even when the system is working normally.
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General Chat / Re: What's your main operating system? (Poll)
« Last post by GreyWoolfe on Today at 01:11:55 AM »
 :-+ and +1 for total commander.  I have been using it for years and can't imagine a computer without it.  It is even installed on my company computers.
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Microcontrollers & FPGA's / Re: LPC4370 Any way to protect firmware?
« Last post by splin on Today at 01:08:39 AM »
If you worry about firmware, use controller with internal flash and memory protection..

You also need to ensure firmware upgrade method is also secure. Assuming you do release firmware upgrades.

If that firmware is on external memory chip, it will be copied in china or where ever copies will come if your product is popular...

Well yes I think you're right - but its a shame as the LPC4370 has that 80MSPS 12bit ADC which is as far as I know is unique for a microcontroller - the fastest I have encountered elsewhere are the 5MSPS 12bit ADCs on some STM32F3 devices. The triple core, HS USB and large internal RAM are also attractive features for the price.

Splin
Its a very unique device, which means its was made for one customer, and then offered to the open market. If it had been developed for a specific application, rather than a specific customer, they would push its suitability for that application.

That's interesting - not something I've seen mentioned anywhere else; do you have any references or links to more information on this or is it not meant to be in the public domain?
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Thanks for all suggestions.

My Arduino code has a watchdog that does reset the CPU in cases of crashes or hangs. The reset code jumps straight to my application where I immediately set the output pins so there is no problem.

The problem arises with resets caused by hardware bugs (I am currently suspecting voltage drops) and in that case the Arduino simply resets while all the other hardware is full power on one of the SSRs. During this power-up reset the Arduino spends a couple of seconds with the output pin open circuit while the rest of the hardware is on full power. Then both SSRs open, causing disastrous effects.

An easy solution which will not require changes to the PCB, is to replace the top, fixed 5V line with another output pin. Then this pin will need to be set to "high" in order to open the top SSR and during resets both pins will be open circuit so both SSRs will be closed.

But this can fail if we force the middle wire to open circuit (even pulled to ground with some resistor) and force the top wire to 5V. This combination may be possible in code crash or some weird bootstrap code. It is basically possible on the Arduino.

A better solution is to have hardware that will make this impossible to happen, and for that it is the 4049/4069 driving the middle pin and ensuring that no matter what the state of the CPU, the middle pin is either 0 or 5V. That would require a change on the PCB to "buffer" the middle wire with one of the 4049/4069's inputs. And one resistor to ground the 4049 input pin. One 14 pin chip and one resistor.

Therefore back to my original question, is there a way to avoid the 14 pin chip + resistor for something smaller? I am struggling for space.



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General Chat / Re: Windows 8ifying of everything, why?
« Last post by GreyWoolfe on Today at 01:05:23 AM »
MacAttak, I'm not sure that 8.1 made the OS tolerable.  A touch centric OS is a touch centric OS and it is just not going to play well or make sense in a desktop environment.|O  I like the idea of classicshell, but the laptops belong to SWMBO and stepdaughter and they are happy with the way the laptops are.  SWMBO even likes Metro :-//  I'm not sure that I will even be able to get them to go to Win 10 but I will try.
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