nRF52832 BT832XE randomly disconnects

RE: nRF52832 BT832XE randomly disconnects

mbates14 — Tue, 21 May 2019 12:15:05 GMT

Yea, Probably so. I didnt know that. Almost sounds like an anti-glitch, glitch detector of sorts. I even tried adding a nice large capacitor right off the BT module, but it still didnt help.

Once I changed out the power supply completely though, all was fine.

RE: nRF52832 BT832XE randomly disconnects

run_ar — Tue, 21 May 2019 12:09:14 GMT

I assume you must have been hitting this: A step increase in supply voltage of 300 mV or more, with rise time of 300 ms or less, within the valid supply range, may result in a system reset. ref: Power-on reset

RE: nRF52832 BT832XE randomly disconnects

mbates14 — Thu, 16 May 2019 11:46:15 GMT

I think I narrowed it down to the power supply. I used a 6V 300mA that was going through a 3.3V regulator. But I changed it out with a 9V 2A and the problem is gone. Funny thing though, my "power led" stayed green the whole time, but I assume an LED is not going to react to spikes in the DC bus. .

RE: nRF52832 BT832XE randomly disconnects

run_ar — Thu, 16 May 2019 09:01:46 GMT

I assume the module manufacturer has a reference layout for their module and that you have followed that? You could also check against the reference layout in nRF52832 product specification against the module.

But are you sure that you everything is soldered correctly and that you do not have additional pieces of wire/shorts or maybe poor soldering connections?

Just so it is clear, this only happens on the custom board? Not the nordic DK?

RE: nRF52832 BT832XE randomly disconnects

mbates14 — Wed, 15 May 2019 14:30:57 GMT

Any critical pull-ups or anything that are required that I may have overlooked?

RE: nRF52832 BT832XE randomly disconnects

mbates14 — Wed, 15 May 2019 14:28:32 GMT

Wont work. Not enough output power. the +19 to +20dbm that the BT832XE produces is crucial.

RE: nRF52832 BT832XE randomly disconnects

Mojo — Wed, 15 May 2019 14:13:10 GMT

May I suggest to try a different module. Like this one https://www.crowdsupply.com/i-syst/blyst-nano

RE: nRF52832 BT832XE randomly disconnects

mbates14 — Wed, 15 May 2019 14:07:04 GMT

Nope, nevermind. Yet another fallacy. I cant track down the problem at all. Its totally random, I disabled the communication error traps, and that fixed my crashing when grounding the RX pin, but it still did NOT fix my problem. I can simply just pickup the PCB and wave it around, and itll disconnect. But I can twist on the board, and it doesnt. I really dont get it.

RE: nRF52832 BT832XE randomly disconnects

mbates14 — Wed, 15 May 2019 13:20:05 GMT

Ok, I got the DevKit doing it. Same exact thing if I mess with the RX pin. This time though, I got an Error Trace:

<error> app: ERROR 4 [NRF_ERROR_NO_MEM] at Z:\Major\Various\Nordic BT\nRF5_SDK_14.2.0_17b948a\examples\ble_peripheral\ble_serial\main.c:1391

Fault Handler 4001, with 0x00000004 error handler. All starts at the UARTE0_UART0_IRQ handler.

(it wont let me copy the stack trace window to bring it in here)

RE: nRF52832 BT832XE randomly disconnects

mbates14 — Wed, 15 May 2019 13:00:40 GMT

I narrowed it down. if the RX pin on the UART gets grounded, it causes the BT module to crash. This seems like an overlooked bug in the SoftDevice, or something. I found a little piece of copper wire stuck in my pins which is why this was happening.

if I physically "ground" the RX pin, even for just a second on the BT module, it'll disconnect. I dont have any pullups or pulldowns on the TX/RX pins, they are connected directly into an xBee module. (its a BT to RF device I made).

Edit: the copper thing was a fallacy. I removed it, it still happens randomly. especially if I am "handling" it.

RE: nRF52832 BT832XE randomly disconnects

mbates14 — Wed, 15 May 2019 12:17:08 GMT

I think there might be something up with the module itself. if I tap on the metal shield, the connection drops. But if I twist/turn on the board, it wont. Its only when I tap.

RE: nRF52832 BT832XE randomly disconnects

mbates14 — Wed, 15 May 2019 11:42:21 GMT

I dont know what an air sniffer trace is, and as I mentioned above, the debug logs are no good because the "j-link debugger" in SEGGER is unaware of the crapout/disconnect. HOWEVER. (there is a however), I can hit "pause" in the debugger after this glitch happens, it pauses at 0xDEADBEEF. Then the top says unknown function at -xDEADBEEE. Also all the CPU registers on the right-hand side are all loaded with 0xdeadbeef.

If I physically disconnect, I can see the DISCONNECTED pop up in the debug log. But, nothing pops up when this happens. I can also instantly reconnect until it disconnects again.

RE: nRF52832 BT832XE randomly disconnects

mbates14 — Wed, 15 May 2019 11:41:11 GMT

Inductors for What DC/DC? There is a 5V to 3.3V DC/DC on my main host PCB, but thats it. Also my signal strength is strong during the whole period its connected, I am monitoring it while its connected through my App. Besides, I have the device sitting right next to it, AND I am using the XE which has an external antenna.

RE: nRF52832 BT832XE randomly disconnects

run_ar — Wed, 15 May 2019 06:26:32 GMT

Also would it be possible to provide debug logs and on air sniffer trace? Are you ending up in any kind of error handler? Can you also check that DEBUG is defined in your debug project?

RE: nRF52832 BT832XE randomly disconnects

Mojo — Tue, 14 May 2019 20:44:39 GMT

Did you check the require clearance for the antenna ? Also check if it has the inductors for the DC/DC ?