cannot pair or advertise HID profile once I toggle gpio pin no. 25 or 26 of nRF52832_WLCSP

[Idan]

To whom it may concern,

I use a BLE app via nRF52832_WLCSP, 'ble_app_hids_keyboard' of SDK11(pca10040),SD s132_nrf52_2.0.0, with the HID profile. once I started advertising BLE and then I toggle gpio pin no. 25 or 26 as a SPI 'chip select' outputs for peripherals(accelerometers) I cannot pair with my central(IOS or Android phones). BLE scanner apps do not show any signs of receiving RSSI data. I must use these exact gpio pins. other gpio pin like 27 or 17 cause nothing alike.

If I start advertising BLE, pair and then I toggle these gpio pins; I can transmit data without any problem noticed.

In the past I used the same app with 'nRF52832_QFN48' I encountered no such problem.

What might be wrong?

Idan

[Idan]

I use the SPI for three other accelerometers with other CS's. they work great, including advertising and leds lightning. it is written in the user manual that: "Radio performance parameters, such as sensitivity, may be affected by high frequency digital I/O with large sink/source current close to the radio power supply and antenna pins.". we used the gpio pins - 25 and 26 as recommended for nRF52832_WLCSP: B3 P0.25 D3 P0.26

and other gpio pins as CS's that works well with advertising: B4 P0.27 A4 P0.29 H2 P0.18

the problematic IO's are not located next to the NFC or radio IO's.

[Hung Bui]

Hi Idan,

Please, describe the steps you do for testing so it's clearer for me. Especially about when you start advertising and when it stopped advertising and what you observe after it stop advertising.

Please send us your schematics, layout. You can send me via PM or via a Mypage case.

Please try to test with simple example (ble_app_hrs for example), and try to toggle those CS pins. I don' t think toggle the CS pin can cause a problem, but maybe the other SPI pins (CLK MISO MOSI) could be the culprit. We need to narrow down the issue.