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PSoC 4 MCU

Anonymous
Not applicable

I have built 100 boards using a PSoC4 BLE (CYBLE4248LQI-583) and I'm discovering that a significant percentage of them have a problem wherein they reset themselves periodically. Some reset as often as every few seconds and others reset much less frequently. The reset interval appears to be somewhat random, but it's hard to tell. I'm somewhat stumped on why this is so I'm looking for some brainstorming help. Below are some additional details. Any ideas?

I've done alot of probing on the boards and can't see anything wrong with the reset line or voltage supplies or anything else in any of the units. I have a 32kHz crystal oscillator and a 24MHz crystal on the board, though I'm using the built-in RC oscillator (IMO) to generate the SysClk because I haven't figured out a way to use the 24 MHz crystal to run my system at 48 MHz. Nominally, I have the device set for 5V though in actuality, it's getting 4.85V.

I have a suspicion that this has something to do with the WDT, which I admittedly don't fully understand. I have a WDT with an ISR, which is getting serviced. I made sure that the WDT ISR is top priority.

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Anonymous
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So I discovered that there is a brownout detection register and it appears that the devices are suffering from brownouts. I then noticed that the Vccd bypass capacitor on my boards got marked as "do not install" by accident. So none of the boards have a bypass capacitor on Vccd.

I installed a 0.1uF cap in that slot because that's the closest thing I had lying around and it looks like it makes a big improvement. So, I think I've found my problem.

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Esteemed Contributor II

Can you please post your complete project or a shortened version that shows the error so that we all can have a look at all of your settings. To do so, use

Creator->File->Create Workspace Bundle (minimal)

and attach the resulting file.

Bob

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Anonymous
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The project is pretty large and I wouldn't expect anyone to parse through the whole thing. Also, this problem only occurs in about 1/3 of the devices I've programmed.

I'm just looking for some brainstorming of things that can cause a device reset.

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Anonymous
Not applicable

So I discovered that there is a brownout detection register and it appears that the devices are suffering from brownouts. I then noticed that the Vccd bypass capacitor on my boards got marked as "do not install" by accident. So none of the boards have a bypass capacitor on Vccd.

I installed a 0.1uF cap in that slot because that's the closest thing I had lying around and it looks like it makes a big improvement. So, I think I've found my problem.

View solution in original post