Controller reset

[Nigel Goodwin]

Separate board for motor may not be possible for us, as we were running products successfully with PIC controller in the same board earlier.

Then move back to the PIC, why change something that's already working?.

 

[piccontrollerlearner]

Then move back to the PIC, why change something that's already working?.

ST provides us more facility in terms of pin numbers and at equal or lower cost

 

[jpanhalt]

It is possible for glitches to cause other resets. For example, they may fire an interrupt or interrupt a communication like I2C. Depending on your software, those false signals might cause a reset.

Presumably, however, the same software that works on a PIC has simply been moved to the new processor. A software-based cause would require the new processor to be more susceptible than a PIC, which I assume in unlikely. I have no experience with ST processors, though.

Since your new design works with battery power but not with the AC power supply, that suggests to me that it is related to the power supply, not software or board layout per se, unless that layout affects the power supply differently than it did with the PIC.

John

 

[Nigel Goodwin]

ST provides us more facility in terms of pin numbers and at equal or lower cost

But the PIC works, the ST doesn't

There are also plenty of higher spec PIC's available - although ST devices seem to be available at 'give away' prices.

 

[piccontrollerlearner]

It is possible for glitches to cause other resets. For example, they may fire an interrupt or interrupt a communication like I2C. Depending on your software, those false signals might cause a reset.

Presumably, however, the same software that works on a PIC has simply been moved to the new processor. A software-based cause would require the new processor to be more susceptible than a PIC, which I assume in unlikely. I have no experience with ST processors, though.

Since your new design works with battery power but not with the AC power supply, that suggests to me that it is related to the power supply, not software or board layout per se, unless that layout affects the power supply differently than it did with the PIC.

John

Ok. Got it.

 

[piccontrollerlearner]

But the PIC works, the ST doesn't

There are also plenty of higher spec PIC's available - although ST devices seem to be available at 'give away' prices.

You are right, Sir. But we have spent months behind the project, from selecting the controller, IDE etc., to reaching to the final stage, as we did not know much about ST.

Almost everything went well and the project is almost ready except for this issue.

That's why we are willing to get it done anyhow.

THANK YOU.

 

[jpanhalt]

When confronted with similar problems of erratic results in real life, the most important step was to find out how to reproduce the problem. As it turned out, the problem was often some detail that seemed unimportant initially.

So far, we have shot suggestions based on experience at solving similar problems. That has not worked. At this point, my advice would be to take a step back and try to make the problem happen consistently. Leave no detail out of consideration, even if it seems illogical at the moment. Can you scope the VDD lines of both the PIC and ST boards? If that is not productive, I would scope pins having the same function on both chips (if possible). Of course, be prepared for the problem to disappear as soon as you add the scope in the mix.

John

 

[alec_t]

the capacitors 10,100,1000 nf also didn't work.

Those are nothing like the 10uF and 100uF that were suggested! Have you tried those suggested values?

 

[piccontrollerlearner]

Those are nothing like the 10uF and 100uF that were suggested! Have you tried those suggested values?

My mistake in posting. Yes, I have tried 10,100,1000 uf capacitors that were suggested.

 

[be80be]

Forgive me if I'm wrong but what st micro are you using cause if the TSSOP20 is it it's not going to work as you have it on the sch.

You need something like this on power rail

 

[jpanhalt]

All we have is the schematic, not the board. I've seen decoupling caps put almost anywhere on the schematic, including up in some isolated corner.

That is not to disagree that they should be very close to the requisite pins. Please note, your 100 uF capacitor seems to be reversed.

Edit: Now the polarity of the electrolytic capacitor in post #30 has been fixed.

 

[be80be]

I fixed that I forgot the flip it top to bottom
But this mess will not work I help someone fix this almost same problem .

The power rail needs to run parallel with the caps across it 104 and 100uf works well
then if needed add a zener diode to clamp the power to 5 volts a head of the caps.

 

[RadioRon]

All we have is the schematic, not the board. .

The board layout was posted in post #4 above.

 

[jpanhalt]

The board layout was posted in post #4 above.

Not in any format I could understand or view. The PDF is unlabeled.

Perhaps, if you could circle and label p7 in that image it would save us all a lot of time.

John

 

[be80be]

The board doesn't have caps in right place. Like I said I helped fix this same problem but they was using a pic 12f chip

Here something I had laying around that shows good layout of caps.

 

[piccontrollerlearner]

Not in any format I could understand or view. The PDF is unlabeled.

Perhaps, if you could circle and label p7 in that image it would save us all a lot of time.

John

Ok. I will post it again.

 

[piccontrollerlearner]

Sorry to all for late response. I have posted screenshot of the PCB design, in which P7 and P8 capacitors are highlighted.
We have replaced p8 by a through hole 10/50 capacitor, and 1117 regulator IC by 7805 and found that the frequency of reset is decreased.

Also, we have made a single sided PCB in which all the components are the same as that shown in the design but are placed on one side of the PCB and that circuit is working properly.

 

[piccontrollerlearner]

There are few other points that I would like to mention

1. The reset occurs mostly when the relay is tripped OFF rather than tripped ON.
2. We have two motors. First, The ac synchronous motor, which is being operated by the relay, and other one is small motor running at 8 rpm through TRIAC. Now, there is no reset when both motors are attached (We have tested for 500 ON/OFF cycles), but as soon as only the small motor is attached, the reset takes place (once in every 50 ON/OFF cycles).