RE: unable to use reset pin as gpio

hmolesworth — Fri, 27 Apr 2018 17:35:38 GMT

I haven't used that pin for SPI. Two things you might try: set the drive strength to high on both high and low after the spi has been set in case it is just too weak

    nrf_gpio_cfg(21,
                 NRF_GPIO_PIN_DIR_OUTPUT,
                 NRF_GPIO_PIN_INPUT_DISCONNECT,
                 NRF_GPIO_PIN_NOPULL,
                 NRF_GPIO_PIN_H0H1,       // Require High Drive both levels
                 NRF_GPIO_PIN_NOSENSE);

and do a run-time check on the pin (not with the command line nrfprog), something similar to this code which I wrote when pins were misbehaving on one of my projects.

const char * FindPinMap(uint16_t PinId)
{
    // 32kHz Osc pins can be used as GPIOs or 32kHz Oscillator, special case
    if ( (PinId == RCC_OSC_OUT_PIN) && (NRF_CLOCK->LFCLKSRC & 0x000001) ) return "RTC-OSC-OUT";
    if ( (PinId == RCC_OSC_IN_PIN)  && (NRF_CLOCK->LFCLKSRC & 0x000001) ) return "RTC-OSC-IN";

    // NFC pins can be used as GPIOs or NFC, special case
    if ( (PinId == NFC1_PIN) && ((NRF_UICR->NFCPINS & UICR_NFCPINS_PROTECT_Msk) == (UICR_NFCPINS_PROTECT_NFC << UICR_NFCPINS_PROTECT_Pos)) ) return "NFC 1";
    if ( (PinId == NFC2_PIN) && ((NRF_UICR->NFCPINS & UICR_NFCPINS_PROTECT_Msk) == (UICR_NFCPINS_PROTECT_NFC << UICR_NFCPINS_PROTECT_Pos)) ) return "NFC 2";

    // Reset pin can be used as GPIOs or nReset, special case
    if ( (PinId == NRESET_PIN)                          // 21
     && (((NRF_UICR->PSELRESET[0] & UICR_PSELRESET_CONNECT_Msk) == (UICR_PSELRESET_CONNECT_Connected << UICR_PSELRESET_CONNECT_Pos))
     &&  ((NRF_UICR->PSELRESET[1] & UICR_PSELRESET_CONNECT_Msk) == (UICR_PSELRESET_CONNECT_Connected << UICR_PSELRESET_CONNECT_Pos))) ) return "nRESET";

    // TRACE pins can be used as GPIOs or Trace, special case
    if ( (CoreDebug->DEMCR & CoreDebug_DEMCR_TRCENA_Msk) == CoreDebug_DEMCR_TRCENA_Msk )
    {
        if (PinId == TRACE_D0_PIN)  return "TRACE D0";  // 18
        if (PinId == TRACE_D1_PIN)  return "TRACE D1";  // 16
        if (PinId == TRACE_D2_PIN)  return "TRACE D2";  // 15
        if (PinId == TRACE_D3_PIN)  return "TRACE D3";  // 14
        if (PinId == TRACE_CLK_PIN) return "TRACE CLK"; // 20
    }

  //if (NRF_SPI0->PSEL.CSN  == PinId) return "SPI0 nCS";
    if (NRF_SPI0->PSEL.SCK  == PinId) return "SPI0 SCK";
    if (NRF_SPI0->PSEL.MOSI == PinId) return "SPI0 MOSI";
    if (NRF_SPI0->PSEL.MISO == PinId) return "SPI0 MISO";

    if (NRF_SPI1->PSEL.SCK  == PinId) return "SPI1 SCK";
    if (NRF_SPI1->PSEL.MOSI == PinId) return "SPI1 MOSI";
    if (NRF_SPI1->PSEL.MISO == PinId) return "SPI1 MISO";

    if (NRF_SPI2->PSEL.SCK  == PinId) return "SPI2 SCK";
    if (NRF_SPI2->PSEL.MOSI == PinId) return "SPI2 MOSI";
    if (NRF_SPI2->PSEL.MISO == PinId) return "SPI2 MISO";

    if (NRF_UARTE0->PSEL.RTS == PinId) return "UartE0 RTS";
    if (NRF_UARTE0->PSEL.CTS == PinId) return "UartE0 CTS";
    if (NRF_UARTE0->PSEL.TXD == PinId) return "UartE0 Tx";
    if (NRF_UARTE0->PSEL.RXD == PinId) return "UartE0 Rx";

    if (NRF_SAADC->CH[0].PSELP == PinId) return "ADC 0+";
    if (NRF_SAADC->CH[0].PSELN == PinId) return "ADC 0-";
    if (NRF_SAADC->CH[1].PSELP == PinId) return "ADC 1+";
    if (NRF_SAADC->CH[1].PSELN == PinId) return "ADC 1-";
    if (NRF_SAADC->CH[2].PSELP == PinId) return "ADC 2+";
    if (NRF_SAADC->CH[2].PSELN == PinId) return "ADC 2-";
    if (NRF_SAADC->CH[3].PSELP == PinId) return "ADC 3+";
    if (NRF_SAADC->CH[3].PSELN == PinId) return "ADC 3-";
    if (NRF_SAADC->CH[4].PSELP == PinId) return "ADC 4+";
    if (NRF_SAADC->CH[4].PSELN == PinId) return "ADC 4-";
    if (NRF_SAADC->CH[5].PSELP == PinId) return "ADC 5+";
    if (NRF_SAADC->CH[5].PSELN == PinId) return "ADC 5-";
    if (NRF_SAADC->CH[6].PSELP == PinId) return "ADC 6+";
    if (NRF_SAADC->CH[6].PSELN == PinId) return "ADC 6-";
    if (NRF_SAADC->CH[7].PSELP == PinId) return "ADC 7+";
    if (NRF_SAADC->CH[7].PSELN == PinId) return "ADC 7-";

    if (NRF_PWM0->PSEL.OUT[0] == PinId) return "PWM0 0";
    if (NRF_PWM0->PSEL.OUT[1] == PinId) return "PWM0 1";
    if (NRF_PWM0->PSEL.OUT[2] == PinId) return "PWM0 2";
    if (NRF_PWM0->PSEL.OUT[3] == PinId) return "PWM0 3";

    if (NRF_PWM1->PSEL.OUT[0] == PinId) return "PWM1 0";
    if (NRF_PWM1->PSEL.OUT[1] == PinId) return "PWM1 1";
    if (NRF_PWM1->PSEL.OUT[2] == PinId) return "PWM1 2";
    if (NRF_PWM1->PSEL.OUT[3] == PinId) return "PWM1 3";

    if (NRF_PWM2->PSEL.OUT[0] == PinId) return "PWM2 0";
    if (NRF_PWM2->PSEL.OUT[1] == PinId) return "PWM2 1";
    if (NRF_PWM2->PSEL.OUT[2] == PinId) return "PWM2 2";
    if (NRF_PWM2->PSEL.OUT[3] == PinId) return "PWM2 3";

    if (NRF_I2S->PSEL.SDOUT == PinId) return "I2S SDOUT";
    if (NRF_I2S->PSEL.SDIN  == PinId) return "I2S SDIN";
    if (NRF_I2S->PSEL.SCK   == PinId) return "I2S SCK";
    if (NRF_I2S->PSEL.MCK   == PinId) return "I2S MCK";
    if (NRF_I2S->PSEL.LRCK  == PinId) return "I2S LRCK";

    // No hardware pins available with these peripherals:
    // NRF_TIMER0                      ((NRF_TIMER_Type          *) NRF_TIMER0_BASE)
    // NRF_TIMER1                      ((NRF_TIMER_Type          *) NRF_TIMER1_BASE)
    // NRF_TIMER2                      ((NRF_TIMER_Type          *) NRF_TIMER2_BASE)
    // NRF_RTC0                        ((NRF_RTC_Type            *) NRF_RTC0_BASE)
    // NRF_RTC1                        ((NRF_RTC_Type            *) NRF_RTC1_BASE)
    // NRF_RTC2                        ((NRF_RTC_Type            *) NRF_RTC2_BASE)

    // Default, no map found
    return "no map";
}

RE: unable to use reset pin as gpio

madblue — Fri, 27 Apr 2018 15:21:13 GMT

Thank you hmolesworth for the support.

we are using a custom board based on bc832. there is nothing connected to the line otherthan a pull up, which can be removed. the pin is directly conncted to the slave data line.

Have you ever tried to use this pin as any communication line like twi or spi. do you think its a bug in the design end or bc832 side.

RE: unable to use reset pin as gpio

hmolesworth — Fri, 27 Apr 2018 14:47:32 GMT

If you have the BC832 dev kit my comment doesn't apply; I see that P0.21 only connected to a push-button on that board

RE: unable to use reset pin as gpio

hmolesworth — Fri, 27 Apr 2018 14:42:05 GMT

In case you are using a development kit similar to the nRF52 dev kit the nRESET pin P0.21 is hardwired to an output on the SAM3 Segger interface via a solder bridge which may be cut. It's SB27 which may be causing the issue you see.

RE: unable to use reset pin as gpio

madblue — Fri, 27 Apr 2018 05:57:39 GMT

Hi kristin,

when i removed the softdevice the gpio started toggling. seems the s132 was causing some issues. Does it work with softdevice?

but now there is a new issue, when i am trying to use this pin for twi its not working properly.ie.. i have connected it to sda line, as it was not working i have used a logic analyzer to view the communication and found that regardless of the what value i am trying to send, it only gives zero.

suppose if i try to write 0x57 to the slave, the values going out is only 0x00. clock and start conditions are going well. There is a 10k pull up connected to the sda line which i have removed as part of debug. it seems some kind of logic level issue is there with the pin.

fyi, the twi slave is working fine with a different gpio pin(02).

RE: unable to use reset pin as gpio

FormerMember — Thu, 26 Apr 2018 13:29:35 GMT

The readout from UICR shows that no pin is set as reset pin.

How do you configure the gpio? Do you use the GPIO HAL?