Search found 37 matches

by PanicanWhyasker
Tue Jun 18, 2019 7:45 am
Forum: Hardware
Topic: What manufacturing defect can cause lack of WiFi functionality?
Replies: 9
Views: 3486

What manufacturing defect can cause lack of WiFi functionality?

Hi, we are manufacturing dozens of ESP32-based devices, and most of them work perfectly. We have a few (e.g. 2% of the production run) which otherwise seem to work fine, as long as the other hardware is related, but the WiFi seems to be dead; the chip WiFi network scan results in 0 networks visible,...
by PanicanWhyasker
Sun Jun 02, 2019 3:07 pm
Forum: Hardware
Topic: Device bricked ("csum err") after two months of service
Replies: 32
Views: 11814

Re: Device bricked ("csum err") after two months of service

The engine signal is optoisolated in the new revision. Also its conditioning circuitry is moved off to a small PCB, separate from the main PCB which has the ESP.
by PanicanWhyasker
Thu May 30, 2019 8:44 pm
Forum: Hardware
Topic: Device bricked ("csum err") after two months of service
Replies: 32
Views: 11814

Re: Device bricked ("csum err") after two months of service

No worries. Yeah, it does seem far fetched, but weirder things have happened. If power consumption isn't an issue, you could easily lower it. Power consumption isn't an issue, I'll lower it. Okay, that makes sense. To clarify, the second batch of devices never overwrite their bootloader? Or they do...
by PanicanWhyasker
Mon May 27, 2019 3:47 pm
Forum: Hardware
Topic: Device bricked ("csum err") after two months of service
Replies: 32
Views: 11814

Re: Device bricked ("csum err") after two months of service

Hello Sam, sorry for the late reply. I wasn't near a PC the last week. Could it be that 360k isnt aggressive enough of a pull down? Hmm, the datasheet states that pin 12 has an internal pull-down during bootstrapping; so it's two pulldowns in parallel, I think this should be enough, as there is real...
by PanicanWhyasker
Wed May 15, 2019 9:25 pm
Forum: Hardware
Topic: Device bricked ("csum err") after two months of service
Replies: 32
Views: 11814

Re: Device bricked ("csum err") after two months of service

Yes, pin 12 is pulled down with 360k to GND. Nothing else drives this pin (it's just the ESP pin, the 360k, and a MOSFET gate). Basically this pin is always logic 0, the only time it's driven high is during lab testing.
by PanicanWhyasker
Fri May 10, 2019 1:04 pm
Forum: Hardware
Topic: Device bricked ("csum err") after two months of service
Replies: 32
Views: 11814

Re: Device bricked ("csum err") after two months of service

@WiFive, no, I cannot correlate it with any write operations. I don't use the NVS or the filesystem. OTA is used regularly, but the failure is not during the OTA, e.g. to give an example - Device X works happily all April - An OTA update is applied on May 3rd - The device continues to work happily, ...
by PanicanWhyasker
Fri May 10, 2019 6:32 am
Forum: Hardware
Topic: Device bricked ("csum err") after two months of service
Replies: 32
Views: 11814

Re: Device bricked ("csum err") after two months of service

@WiFive, my programming sequence is that the ESP with the blank flash chip is first powered through the normal power source, likely for more than 5 seconds. Only then I connect the serial harness and run esptool. Also, the devices flashed like this work. They work continuously for months, they devel...
by PanicanWhyasker
Fri May 10, 2019 5:27 am
Forum: Hardware
Topic: Device bricked ("csum err") after two months of service
Replies: 32
Views: 11814

Re: Device bricked ("csum err") after two months of service

Yeah, I haven't got to the hardware interventions part, because - only this sector shows defective, and I'm reading 1 MB, if it were an electrical issue during reading, I'd expect to affect 100% of the dumps - also (based on experience from other devices), when you overwrite this sector, the weak bi...
by PanicanWhyasker
Thu May 09, 2019 4:59 pm
Forum: Hardware
Topic: Device bricked ("csum err") after two months of service
Replies: 32
Views: 11814

Re: Device bricked ("csum err") after two months of service

Lol, what an interesting development... I got two devices back, both "bricked" in the same way. "62" is encrypted, and shows damage in its first bootloader sector; its entropy is only ~0.62 and the histogram shows high prevalence of bytes towards 0xff. More interestingly, as discussed earlier in the...

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