Pin P0.00 as a button input not working as GPIO but P0.01 does. Already switched all LFCLKSRC to RC.

[jm47895]

Board: NRF52840

SDK: 16

Soft Device: s113

So our board is custom and does not contain a crystal. We are treating P0.00 and P0.01 as GPIOs for button inputs. P0.01 works fine but P0.00 does not work and no events are produced despite both being programmed the exact same way.  

I understand that those pins are reserved as crystal pins and according to other posts in this forum you should switch all LFCLKSRC to RC when you want to use them as GPIO. This has been done and does not fix the issue. In addition there are no NULL values in the pin configuration. The EE tested the voltage and found that it is oscillating between hi and low when the button is not pressed. Below is how the pins are configured with BSP_BUTTON_0 being the button not working correctly: 

static const app_button_cfg_t app_buttons[BUTTONS_NUMBER] =
{
    #ifdef BSP_BUTTON_0
    {BSP_BUTTON_0, APP_BUTTON_ACTIVE_LOW, NRF_GPIO_PIN_NOPULL, bsp_button_event_handler},
    #endif // BUTTON_0

    #ifdef BSP_BUTTON_1
    {BSP_BUTTON_1, APP_BUTTON_ACTIVE_LOW, NRF_GPIO_PIN_NOPULL, bsp_button_event_handler},
    #endif // BUTTON_1

    #ifdef BSP_BUTTON_2
    {BSP_BUTTON_2, APP_BUTTON_ACTIVE_LOW, NRF_GPIO_PIN_PULLUP, bsp_button_event_handler},
    #endif // BUTTON_2

    #ifdef BSP_BUTTON_3
    {BSP_BUTTON_3, APP_BUTTON_ACTIVE_LOW, NRF_GPIO_PIN_NOPULL, bsp_button_event_handler},
    #endif // BUTTON_3

    #ifdef BSP_BUTTON_4
    {BSP_BUTTON_4, APP_BUTTON_ACTIVE_LOW, NRF_GPIO_PIN_NOPULL, bsp_button_event_handler},
    #endif // BUTTON_4

    #ifdef BSP_BUTTON_5
    {BSP_BUTTON_5, APP_BUTTON_ACTIVE_LOW, NRF_GPIO_PIN_NOPULL, bsp_button_event_handler},
    #endif // BUTTON_5

    #ifdef BSP_BUTTON_6
    {BSP_BUTTON_6, APP_BUTTON_ACTIVE_LOW, NRF_GPIO_PIN_NOPULL, bsp_button_event_handler},
    #endif // BUTTON_6

    #ifdef BSP_BUTTON_7
    {BSP_BUTTON_7, APP_BUTTON_ACTIVE_LOW, NRF_GPIO_PIN_NOPULL, bsp_button_event_handler},
    #endif // BUTTON_7

    #ifdef BSP_BUTTON_8
    {BSP_BUTTON_8, APP_BUTTON_ACTIVE_LOW, NRF_GPIO_PIN_NOPULL, bsp_button_event_handler},
    #endif // BUTTON_8

    #ifdef BSP_BUTTON_9
    {BSP_BUTTON_9, APP_BUTTON_ACTIVE_LOW, NRF_GPIO_PIN_NOPULL, bsp_button_event_handler},
    #endif // BUTTON_9
};

Given this information, any information that could solve this issue with the button not working?    

[Simonr]

Hi

What did you change in order to set the LFCLKSRC to use the RC oscillator exactly? The recommendation is to make these changes to the following function in your sdk_config.h file:

// <h> Clock - SoftDevice clock configuration

//==========================================================
// <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

P0.00 and P0.01 should behave identically when the RC oscillator is enabled, so the only two things I can think of that would cause something like this is either the LFCLKSRC not being configured correctly to use the RC oscillator, or that there's a HW issue where the P0.00 pin is soldered incorrectly. Can you check your custom board to make sure that it's not a disconnect or short somewhere on the P0.00 line.

Best regards,

Simon

[jm47895]

Hey Simon, 

Yeah I changed the SDK options for XTAL in three places: 

// <e> NRFX_CLOCK_ENABLED - nrfx_clock - CLOCK peripheral driver
//==========================================================
#ifndef NRFX_CLOCK_ENABLED
#define NRFX_CLOCK_ENABLED 1
#endif
// <o> NRFX_CLOCK_CONFIG_LF_SRC  - LF Clock Source
 
// <0=> RC 
// <1=> XTAL 
// <2=> Synth 
// <131073=> External Low Swing 
// <196609=> External Full Swing 

#ifndef NRFX_CLOCK_CONFIG_LF_SRC
#define NRFX_CLOCK_CONFIG_LF_SRC 0
#endif

// <e> NRF_CLOCK_ENABLED - nrf_drv_clock - CLOCK peripheral driver - legacy layer
//==========================================================
#ifndef NRF_CLOCK_ENABLED
#define NRF_CLOCK_ENABLED 1
#endif
// <o> CLOCK_CONFIG_LF_SRC  - LF Clock Source
 
// <0=> RC 
// <1=> XTAL 
// <2=> Synth 
// <131073=> External Low Swing 
// <196609=> External Full Swing 

#ifndef CLOCK_CONFIG_LF_SRC
#define CLOCK_CONFIG_LF_SRC 0
#endif

// </h> 
//==========================================================

// <h> Clock - SoftDevice clock configuration

//==========================================================
// <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

Are there any specific settings elsewhere that need to be set when switching to RC?