Questions about PCBs that do not work normally

RE: Questions about PCBs that do not work normally

SHMoon — Wed, 10 May 2023 01:18:43 GMT

hello,

I have already changed to an internal RC oscillator and am using it.

As I mentioned, reducing the advertising time..

It is a state in which similar problems do not occur.

I'll do some more testing and get back to you if there are any issues.

thank.

RE: Questions about PCBs that do not work normally

Simonr — Tue, 09 May 2023 07:35:08 GMT

Thank you for clarifying!

Have you changed your application configurations to use the internal RC oscillator in your ble_app_uart application? You need to set these configs in sdk_config.h to the following values:

//==========================================================
// <o> NRF_SDH_CLOCK_LF_SRC  - SoftDevice clock source.

// <0=> NRF_CLOCK_LF_SRC_RC
// <1=> NRF_CLOCK_LF_SRC_XTAL
// <2=> NRF_CLOCK_LF_SRC_SYNTH

#ifndef NRF_SDH_CLOCK_LF_SRC
#define NRF_SDH_CLOCK_LF_SRC 0
#endif

// <o> NRF_SDH_CLOCK_LF_RC_CTIV - SoftDevice calibration timer interval.
#ifndef NRF_SDH_CLOCK_LF_RC_CTIV
#define NRF_SDH_CLOCK_LF_RC_CTIV 16
#endif

// <o> NRF_SDH_CLOCK_LF_RC_TEMP_CTIV - SoftDevice calibration timer interval under constant temperature.
// <i> How often (in number of calibration intervals) the RC oscillator shall be calibrated
// <i>  if the temperature has not changed.

#ifndef NRF_SDH_CLOCK_LF_RC_TEMP_CTIV
#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2
#endif

// <o> NRF_SDH_CLOCK_LF_ACCURACY  - External clock accuracy used in the LL to compute timing.

// <0=> NRF_CLOCK_LF_ACCURACY_250_PPM
// <1=> NRF_CLOCK_LF_ACCURACY_500_PPM
// <2=> NRF_CLOCK_LF_ACCURACY_150_PPM
// <3=> NRF_CLOCK_LF_ACCURACY_100_PPM
// <4=> NRF_CLOCK_LF_ACCURACY_75_PPM
// <5=> NRF_CLOCK_LF_ACCURACY_50_PPM
// <6=> NRF_CLOCK_LF_ACCURACY_30_PPM
// <7=> NRF_CLOCK_LF_ACCURACY_20_PPM
// <8=> NRF_CLOCK_LF_ACCURACY_10_PPM
// <9=> NRF_CLOCK_LF_ACCURACY_5_PPM
// <10=> NRF_CLOCK_LF_ACCURACY_2_PPM
// <11=> NRF_CLOCK_LF_ACCURACY_1_PPM

#ifndef NRF_SDH_CLOCK_LF_ACCURACY
#define NRF_SDH_CLOCK_LF_ACCURACY 1
#endif

When connected to a debugger the clock calibration is not necessary, which explains why you're able to connect when connected to a J-Link device.

Regarding your advertising interval, the values you've set are very high 2500 equals to 1.5 seconds, while 7500 equals to advertising every ~4.7 seconds. Although both are within the BLE specification, it will be hard for a scanner to find and connect to an advertising device only advertising every 4.7 seconds.

Best regards,

Simon

RE: Questions about PCBs that do not work normally

SHMoon — Tue, 09 May 2023 02:20:37 GMT

hello,

Thanks for the reply. As you said,

I'm using the ble_app_uart example.

1. Restatement of the problem Symptom

1) Peripheral mode, but not connected to Central Symptom

2) Uart communication ----- External uart to usb (com port) ---- PC terminal ---> Data not received

(Check if the PC's Com port driver is normal)

2. Operation when connecting J-Link to connector (physically only)

- Physically plug in J-Link socket -> Connected to Central while receiving data from Terminal

3. Using 32.768 kHz Crystal

- Using internal crystal

4. Usage circuit diagram

Additional doubts are

- Advertising settings in the past : define APP_ADV_INTERVAL 2500 /**< The advertising interval (in units of 0.625 ms. This value corresponds to 40 ms). */

- Advertising setting when the problem occurs : #define APP_ADV_INTERVAL 7500

Perhaps, the advertising time was too long and did not stick While inserting the J-Link into the socket,

I think that the nRF52 may have been reset and reattached...

Please review if there are any strange parts.

RE: Questions about PCBs that do not work normally

Simonr — Mon, 08 May 2023 12:22:56 GMT

1. Do you mean that it doesn't connect automatically to the serial terminal the UART was connected to? How does the UART interface with the PC in your design? On the development kit it has a UART interface through a virtual COM port for example. Also, what serial terminal are you using on the computer side, and can you describe the "incomprehensible" behavior in detail?

2. This makes it seem like you're using the ble_app_uart example project and not the peripheral\UART example. Can you confirm which one you're using? A reason why it would connect when connected to a J-Link device is either that it is now powered correctly or that its using a correctly calibrated 32.768 kHz crystal. Can you share some details on what 32.768kHz crystal your design is using.

Please also upload the schematics of your design instead of just the reference circuitry from our PS.

Best regards,

Simon