BLE Secure bootloader SD clock issues

RE: BLE Secure bootloader SD clock issues

bjorn-spockeli — Thu, 12 Dec 2019 09:27:47 GMT

Hi Peter,

Aha, that explains it. Anyways, happy to hear that things are working as they should!

Happy to help 🙂

Best regards

Bjørn

RE: BLE Secure bootloader SD clock issues

pjboudewijns — Thu, 12 Dec 2019 09:08:23 GMT

Hi Bjorn,

You are so right! I am using the nRF Connect app. But to my shame I discovered I was still using an RSSI filter that was critical. So most of the time the RF signal from my board didn't exceed the threshold. And thus, the device did not appear in the app leading me to conclude it was not transmitting. Stupid mistake. So now the bootloader and my own buttonless DFU application both work super!

Thanks for your support. Nordic rocks :-)

PeTer

RE: BLE Secure bootloader SD clock issues

bjorn-spockeli — Thu, 12 Dec 2019 08:05:21 GMT

The LFCLK setting should not affect the "discoverablity" of the device. Its the advertisment interval that will determine how quickly a device is "found" by a BLE Central that is scanning. WHich mobile app are you using to scan for BLE devices?

Best regards

Bjørn

RE: BLE Secure bootloader SD clock issues

pjboudewijns — Wed, 11 Dec 2019 14:29:11 GMT

Hi Bjorn,

No, my own design does not have a 32.768 kHz crystal. So I already experimented with the settings you mentioned. Right now my bootloader is functional, but is looks like the changed setting has a great influence on the BLE functionality. When I start the device without a valid application it sometimes takes almost 30 seconds before the device is 'found' by the app on my phone. Sometimes it cant be found at all.

When found, I can perform an OTA DFU with my own application based on the BUTTONLESS_DFU example. So I've made a huge leap forward. But my only concern is the seemingly 'unstable' behaviour on BLE.

RE: BLE Secure bootloader SD clock issues

bjorn-spockeli — Wed, 11 Dec 2019 14:06:39 GMT

Hi Peter,

Does your custom board have the external 32.768 kHz crystal? If it does not, then you need to configure the SoftDevice to use the internal RC oscillator by setting the following defines in the sdk_config.h file in both the bootloader project and in your application project.

#define NRF_SDH_CLOCK_LF_SRC 0

#define NRF_SDH_CLOCK_LF_RC_CTIV 16

#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2

#define NRF_SDH_CLOCK_LF_ACCURACY 1

Best regards

Bjørn