spim_instance.p_reg->PSELDCX not writable causes P0.0 to be uninitialized by nrfx_spim_uninit

[Hash0]

Hi everyone,

I am trying to use P0.0 but it keeps getting uninitialized when calling nrfx_spim_uninit.

nrfx_spim.c line 659 keeps uninitializing P0.0

#if NRFY_SPIM_HAS_DCX
        spim_pin_uninit(ext_pins.dcx_pin);
#endif

It is because in nrf_spim.h line 1431 does not change the value of PSELDCX:

#else
    p_reg->PSELDCX = dcx_pin;
#endif

Is there a way to change NRFY_SPIM_HAS_DCX without modifying the library?

I do not need DCX in my application.

This code on the nRF52840DK will reproduce the bug:

#include <zephyr/kernel.h>
#include <nrfx_spim.h>
#include <hal/nrf_gpio.h>

static nrfx_spim_t spim_inst = NRFX_SPIM_INSTANCE(NRF_SPIM0);
static nrfx_spim_config_t config = NRFX_SPIM_DEFAULT_CONFIG(28, 29, 30, 31);
static uint32_t pin_num = 0;

static void spim_example()
{
	nrf_gpio_cfg_output(pin_num);

	printk("pin dir before: %x\n", nrf_gpio_pin_dir_get(pin_num));

	nrfx_spim_init(&spim_inst, &config, NULL, NULL);
	nrfx_spim_uninit(&spim_inst);

	printk("pin dir after: %x\n", nrf_gpio_pin_dir_get(pin_num));
}

static void register_example()
{
	printk("PSELDCX before: %x\n", spim_inst.p_reg->PSELDCX);
	spim_inst.p_reg->PSELDCX = 0xAAAAAAAA;
	printk("PSELDCX after: %x\n", spim_inst.p_reg->PSELDCX);
}

int main(void)
{
	spim_example();
	register_example();
	return 0;
}

output:

*** Booting nRF Connect SDK v3.3.0-ba167d9f3db4 ***
*** Using Zephyr OS v4.3.99-fd9204a02d52 ***
config.dcx_pin: ffffffff
pin dir before: 1
pin dir after: 0
PSELDCX before: 0
PSELDCX after: 0

[Pallavi Patil]

Hie HashO,

I tried your code and was getting the same error as yours. Can you please check if including the following fixes you issue:
Include this in your Cmake.txt
zephyr_compile_definitions(SPIM_DCX_DISCONNECTED_READBACK=0).



This is now not uninitializing P0.0.

Please let us know if this solution works or we can find roundabout.

Best Regards

Pallavi

[Hash0]

This works! Thank you very much.