nrf9160 gpio low is not voltage 0, help

[fatalfeel]

const struct device* gpio_dev = device_get_binding("GPIO_0");
err = gpio_config(gpio_dev,
tx_pin,
NRF_GPIO_PIN_S0S1);

for(i=0 ;; i++)
{
printk("nrf_gpio_pin_write");

if( i%2 == 0 )
nrf_gpio_pin_write(tx_pin, 0);
else
nrf_gpio_pin_write(tx_pin, 1);

k_usleep(100000);
}

the low voltage is 1.2v

/// nRF9160_PS_v2.0.pdf p. 101

nrfjprog -f NRF91 --memrd 0x50842504 --w 16 --n 64
0x50842504: 0002 1400 0002 1400 0002 1400 0043 D400 |............C...|
0x50842514: 8002 1400 8002 1400 8002 1400 0000 0000 |................|
0x50842524: 0000 0000 0000 0000 0000 0000 0000 0000 |................|
0x50842534: 0000 0000 0000 0000 0000 0000 0000 0000 |................|

///

how to change to 0v

[fatalfeel]

/////////////I got answer

static void Test_GPIOTE()
{
int i;
int err;

nrfx_gpiote_in_config_t in_config =
{
.sense = NRF_GPIOTE_POLARITY_LOTOHI,
.pull = NRF_GPIO_PIN_PULLUP,
.is_watcher = false,
.hi_accuracy = true,
.skip_gpio_setup = false
};

IRQ_DIRECT_CONNECT(GPIOTE0_IRQn, 0, nrfx_gpiote_irq_handler, 0);
irq_enable(GPIOTE0_IRQn);

err = nrfx_gpiote_init(0);
if (err != NRFX_SUCCESS)
{
printf("nrfx_gpiote_init error: %08x", err);
return;
}

err = nrfx_gpiote_in_init(rx_pin, &in_config, rx_event_handler);
if (err != NRFX_SUCCESS)
{
printf("nrfx_gpiote_in_init error: %08x", err);
return;
}

nrfx_gpiote_in_event_enable(rx_pin, true);

////////////////////////////////can not before nrfx_gpiote_init and nrfx_gpiote_out_init(tx_pin, &out_config); ////////////////////////////////
////////////////beause nrfx_gpiote_init call -> nrf_gpio_cfg_output of ~/ncs/modules/hal/nordic/nrfx/hal/nrf_gpio.h
//add this
nrf_gpio_cfg(tx_pin,
NRF_GPIO_PIN_DIR_OUTPUT,
NRF_GPIO_PIN_INPUT_DISCONNECT,
NRF_GPIO_PIN_NOPULL,
NRF_GPIO_PIN_H0H1,       //use this, low will be 0.4v
NRF_GPIO_PIN_NOSENSE);

///////////////////////////////////////////////////

for(i=0 ;; i++)
{
printk("nrf_gpio_pin_write");

if( i%2 == 0 )
nrf_gpio_pin_write(tx_pin, 0);
else
nrf_gpio_pin_write(tx_pin, 1);

k_usleep(10000);
}
}

//////////////////////////////////////////////////////////////////////////////another problm
now high is 1.8v and low is 0.45v

Could set low to 0.0v

Can software to do this?

or need hardware to solve?

[fatalfeel]

now high is 1.8v and low is 0.45v

Could set low to 0.0v

Can software to do this?

or need hardware to solve?

[Kenneth]

fatalfeel said:

Can software to do this?

 No. It must be some external hardware.

[fatalfeel]

thanks a lot man~~~~