Can not program device

RE: Can not program device

Sergy — Tue, 29 Dec 2015 09:41:52 GMT

Err ok, then no, they are relatively long, but maximum 3cm, not longer.

RE: Can not program device

Hung Bui — Tue, 29 Dec 2015 09:29:22 GMT

Hi Sergey,

I suspect the long pin traces could cause an issue, if it's longer than 15cm I would suggest you to add external pull up (SWDIO) and pull down (SWDCLK) resistors.

RE: Can not program device

Sergy — Mon, 28 Dec 2015 08:38:59 GMT

There is no reset happening during the normal operation, but may be in debug there are some special conditions that trigger it?

Ive submitted schematics and layout via support page. SWD pin traces are pretty long indeed. We are working on adding bigger capacitor, but that was to pass a CE requirement, it might help overal system stability as well, Ill keep you posted.

RE: Can not program device

Hung Bui — Tue, 22 Dec 2015 13:12:14 GMT

Sorry, I am not very familiar with the GSM module, quite surprised that it can get to 2A. I was suspecting that the high peak current can cause voltage drop and then cause the nRF51 to reset.

I assume that you have set the optimization level to 0. Do you have very long track for SWD pins ?

Your issue sounds pretty similar to this one. Could you try to isolate the nRF51 from the rest of the board ?

You can send us your schematic and layout to our support portal (MyPage) for further investigation.

RE: Can not program device

Sergy — Tue, 22 Dec 2015 09:23:33 GMT

No, its normal for GSM module to have peak current 1.6-2A, they are very short spikes, but that does happen. Not sure why you are surprised? There is no optimization turned on. When I start the debug It stops on main but once I press StepOver first function which is nothing else than setting pin to output and setting it on I get a warning that Processor cant be halted and the whole bunch of register read errors. Please see the screenshot in attachment: Screenshot So it doesnt even go into GSM part it starts behaving weirdly on the first command.

RE: Can not program device

Hung Bui — Tue, 22 Dec 2015 08:33:56 GMT

@Sergey: Are you sure ? 1.6A is a little bit too high. When you mentioned you can't do step-by-step debugging, what exactly happened ? Have you made sure you don't use any code optimization (in C/C++ tab in setting). With optimization you won't be able to debug. If you only try to debug very simple code (without GSM for example), would it work?

RE: Can not program device

Sergy — Mon, 21 Dec 2015 22:03:23 GMT

Hello Hung, it has SD programmed on it, but it doesnt use it and yes GSM has about 1.6A peak current.

RE: Can not program device

Hung Bui — Mon, 21 Dec 2015 16:40:25 GMT

Hi Sergey, Does the application use the softdevice ? Would the GSM have a high peak current ?

RE: Can not program device

Sergy — Mon, 21 Dec 2015 14:56:57 GMT

Hello, the pin controls the switch which is transistor+mosfet. There is no voltage/current coming into this pin, its only output. So when pin is high it turns on transistor which in turn turns on FET that provides 4v to GSM module. My main problem to be honest is that I cant do any step-by-step debugging in Keil, but in the running mode it works fine.

RE: Can not program device

Hung Bui — Mon, 21 Dec 2015 12:51:02 GMT

Hi Sergey,

It's not clear for me if the 4V is connected directly to the chip (via GPIO pin or via VDD pins) or not. Note that the maximum voltage a pin can take is VDD+0.3. And maximum input for VDD is 3.6V.

RE: Can not program device

Sergy — Sun, 20 Dec 2015 05:36:05 GMT

I also noticed that If I dont connect UART interface on pins 26 and 45 I can reprogram chip just fine even when I have 4v enabled.