nRF52 changing PIO from Analog to Digital Output

RE: nRF52 changing PIO from Analog to Digital Output

AmitKumar — Fri, 28 Oct 2016 09:59:48 GMT

For P0.22 - This seems to be sporadic, i will get back on it. But the Pio is not being used by SPI, it is separate from pins configured for SPI.

Thanks.

RE: nRF52 changing PIO from Analog to Digital Output

Jørgen Holmefjord — Thu, 27 Oct 2016 12:32:32 GMT

Which SDK version are you using? Which pins are configured for NRF_DRV_SPI_DEFAULT_CONFIG? Can you toggle the pin if you explicitly specify all SPI pins to be other pins than P0.22?

RE: nRF52 changing PIO from Analog to Digital Output

Jørgen Holmefjord — Thu, 27 Oct 2016 12:22:53 GMT

On the nRF52-DK you have to cut and solider SB1-SB4 to disconnect the external 32 kHZ crystal, to use the pins as GPIO. Make sure your application is not configured to use external crystal. To use RESET pin (P0.21) as GPIO, you need to remap the RESET pin in the UICR registers, and solider SB17 on nRF52-DK.

RE: nRF52 changing PIO from Analog to Digital Output

AmitKumar — Thu, 27 Oct 2016 12:19:43 GMT

Hi,

Within the same code (the overall project is trying to use PIO1 as chip select for the flash), I am not able to toggle the PIO22 (like below) also, without commenting out nrf_drv_spi_init and nrf_drv_spi_transfer. This code is the spi example from keil5 with SPI pins reassigned from default to flash. Behaviour is identical to what we are observing on nRF52-DK.

nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG(SPI_INSTANCE);
spi_config.ss_pin = SPI_CS_PIN;
//APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler));
		
nrf_gpio_cfg_output(22);
    
while(1)
{
			

        // Reset rx buffer and transfer done flag
        memset(m_rx_buf, 0, m_length);
        spi_xfer_done = false;
	    m_tx_buf[0] = 0x5;
        m_length = 1;
	    m_length2 = 4;
	   m_rx_buf[0] = m_rx_buf[1] = m_rx_buf[2] = m_rx_buf[3] = 0xAA;
	   //APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length2));


        while(spi_xfer_done == false)
        {
            __SEV();
            __WFE();
            __WFE();
        }

        LEDS_INVERT(BSP_LED_0_MASK);
	    nrf_delay_ms(1000);
	    nrf_gpio_pin_toggle(22);

}

Thx, AmitKumar

RE: nRF52 changing PIO from Analog to Digital Output

AmitKumar — Thu, 27 Oct 2016 11:50:08 GMT

We tested it on nRF52-DK as well. If we can switch it on there, that will also help.

RE: nRF52 changing PIO from Analog to Digital Output

Jørgen Holmefjord — Thu, 27 Oct 2016 11:33:11 GMT

Are you using the nRF52-DK or a custom board?

RE: nRF52 changing PIO from Analog to Digital Output

Jagadish.H — Thu, 27 Oct 2016 11:28:36 GMT

this is more specific to the device that could also be using the same PIO, not just analog. for eg: PIO1 can be used as XL2 input, as well as Digital IO, The functions you have suggested are not doing the job. I need to switch the PIO1 to Digital IO, as described in the product datasheet (on page 13, nRF52832_PS_v1.2). I have exact same issue with GPIO 21, which is stuck in nReset, that also needs to be switched to Digital IO.

RE: nRF52 changing PIO from Analog to Digital Output

Jørgen Holmefjord — Thu, 27 Oct 2016 08:35:07 GMT

Hi,

There are no analog outputs on the nRF52, as this would require a DAC. The closest to analog output will be to output PWM signals on the pins.

Take a look at the GPIO abstraction API documentation about how to configure GPIO. The simples configuration of an output would be to call the function nrf_gpio_cfg_output(uint32_t pin_number).

Best regards,

Jørgen