nrf51 wont run without debugger

RE: nrf51 wont run without debugger

Vidar Berg — Tue, 14 Feb 2017 14:29:16 GMT

could it be that semihosting is enabled (relevant if GCC toolchain is used)? -> https://devzone.nordicsemi.com/question/84130/nrf52-does-not-start-without-debugger/

RE: nrf51 wont run without debugger

FormerMember — Tue, 14 Feb 2017 13:54:33 GMT

Okay, the chip version is compatible with the softdevice version you are using.

RE: nrf51 wont run without debugger

FormerMember — Tue, 14 Feb 2017 13:53:57 GMT

Could you check the following:

1) When not in debug mode, does the code start running? You can check this by making an LED blink.

2) What is the ramp-up time of VDD?

3) The GPIOs, are any of the GPIOs connected to something that still has a voltage when VDD is 0?

RE: nrf51 wont run without debugger

Jim Peschke — Mon, 13 Feb 2017 14:16:30 GMT

Kristin, the chip is CF AC A0. The soft device version is s130v1

RE: nrf51 wont run without debugger

Jim Peschke — Mon, 13 Feb 2017 12:34:27 GMT

Kristin, I don't know but I will get those answers. One thing I've learned is that if I pull SWDIO low momentarily, the chip comes up 100% of the time, and stays up until power is removed. This almost certainly tells me that the chip is stuck in some mode that can be reset out of. An external POR circuit is not an option here due to size restrictions.

RE: nrf51 wont run without debugger

FormerMember — Mon, 13 Feb 2017 10:01:53 GMT

Jim Peschke: What is the chip revision of the chip you are using? Do you use a softdevice, if so, which version? The chip revision vs chip markings can be found in this compatibility matrix.

RE: nrf51 wont run without debugger

Jim Peschke — Thu, 09 Feb 2017 16:17:19 GMT

Thanks Daniel. Modding this board is a challenge, but if we don't get somewhere soon we'll probably try removing the pullup on SWDIO. Software engineer says she is using RC clock.

RE: nrf51 wont run without debugger

butch — Thu, 09 Feb 2017 12:14:38 GMT

If touching the SWDIO line with probe has an effect...there is another thread in this forum that suggests adding a small capacitor. But I recall it was about the SWDCLK line, and was about using too much power since running in DEBUG mode.

RE: nrf51 wont run without debugger

Daniel Wang — Wed, 08 Feb 2017 22:06:22 GMT

Yes, ask the SW developer about that! All the BLE examples in the SDK is configured to use external 32 kHZ crystal, so it's crucial to configure the SoftDevice to use the RC oscillator on boards that don’t have an external 32 kHz crystal. On the newest reference design a 1K ohm pulldown on SWDCLK is added, anything other than that is a bit “overkill”. No need for external pullup on SWDIO.

RE: nrf51 wont run without debugger

Jim Peschke — Wed, 08 Feb 2017 21:56:26 GMT

I am considering removing the 12k pullup on SWDIO, since the Nordic reference design doesn't have it (but it DOES have the 12k pulldown on SWCLK, so it stays). We've had trouble with them before, but we might have been using older NRF51s.

I do NOT have a 32kHz crystal. I will ask the software developer about that!

RE: nrf51 wont run without debugger

Daniel Wang — Wed, 08 Feb 2017 21:55:57 GMT

Use this clock config:

nrf_clock_lf_cfg_t rc_cfg = {
   .source = NRF_CLOCK_LF_SRC_RC,
   .rc_ctiv = 16, // Check temperature every 4 seconds
   .rc_temp_ctiv = 2, // Calibrate at least every 8 seconds even if the temperature hasn't changed
};

RE: nrf51 wont run without debugger

Daniel Wang — Wed, 08 Feb 2017 21:52:08 GMT

Do you have external 32kHz crystal on the board? If not, make sure that the SoftDevice is configured to use the internal RC oscillator.

RE: nrf51 wont run without debugger

Roger Clark — Wed, 08 Feb 2017 21:47:08 GMT

Have you tried removing those resistors. They are not mandatory, they are just a precaution, and are not supposed to be so necessary on newer versions of the nRF51 (though older versions were supposed to be prone to being locked in debug mode)

RE: nrf51 wont run without debugger

Jim Peschke — Wed, 08 Feb 2017 21:45:27 GMT

Yes, I have an external 12k pullup on SWDIO and a 12k pulldown on SWDCLK. I am not the software developer. I know that the application we are testing on now uses the softdevice. The chip very much acts like its stuck in an undefined state until the SWDIO/RESET line is moved. I am asking the software developer to test this my manually cycling the SWDIO/RESET line.

RE: nrf51 wont run without debugger

Daniel Wang — Wed, 08 Feb 2017 21:35:51 GMT

You have 12k external pulldown/pullup on the SWD lines?? Do you have this issue if you try to program an application that doesn’t use the softdevice? Or does the issue occur only for the BLE examples in the SDK?

RE: nrf51 wont run without debugger

Jim Peschke — Wed, 08 Feb 2017 21:14:01 GMT

I connect four wires: SWDIO, GND, SWCLK, and Power (which is 2.8V for odd reasons, not 3.3V). I noticed that one of the reference designs does NOT have any external pullup on SWDIO. The manual says this pin is internally pulled up. I have a previous design where these four signals have identical wiring, and I have not encountered this problem before.

RE: nrf51 wont run without debugger

Roger Clark — Wed, 08 Feb 2017 20:59:27 GMT

When you connect the debugger, which wires do you connect ?

GND, SWDIO, SWCLK , 3.3V etc

Have you tried just connecting the ground and other wires, one by one and see if any particular wire makes it work