Interrupt called only once during read/write to NFC tag application and then doesn't when tag is detected

[Atomic1]

Hello,

I am using STEVAL25R200 evaluation board and integrating read/write application using the ndef_read/write examples provided in the documentation embedded library. In my main function, I am Initializing the NFC using rfalNfcInitialize(), rfalNfcDeactivate() and rfalNfcDiscover().

In the while loop, using the rfalWorker() function, I am polling for NFC tags. I have checkd using the EVAL GUI software that a NFC V tag in indeed present and being detected along with its ID (e002080ab3e64bc8).

However, the tag is not detected in my code. I get the rfaNfcGetState = RFAL_NFC_STATE_POLL_TECHDETECT on my serial terminal and then it waits indefinitely. In my opinion, the activation of tag needs to happen using Interrupt routine but it never gets called and I never even proceed further. I have set my IRQ (PA0) and SS (PB0) pins in nfc_conf.h and initialized the IRQ pin as follows.

#define BUS_SPI1_NSS_GPIO_PIN GPIO_PIN_0
#define BUS_SPI1_NSS_GPIO_PORT GPIOB
#define BUS_SPI1_IRQ_GPIO_PIN GPIO_PIN_0
#define BUS_SPI1_IRQ_GPIO_PORT GPIOA

#define ST25R_SS_PIN BUS_SPI1_NSS_GPIO_PIN /*!< GPIO pin used for ST25R SPI SS */
#define ST25R_SS_PORT BUS_SPI1_NSS_GPIO_PORT /*!< GPIO port used for ST25R SPI SS port */

#define ST25R_INT_PIN BUS_SPI1_IRQ_GPIO_PIN /*!< GPIO pin used for ST25R IRQ */
#define ST25R_INT_PORT BUS_SPI1_IRQ_GPIO_PORT

________________________________________________

void platformIrqST25RPinInitialize(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};

__HAL_RCC_GPIOA_CLK_ENABLE();

GPIO_InitStruct.Pin = GPIO_PIN_0;
GPIO_InitStruct.Mode = GPIO_MODE_IT_FALLING;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

HAL_NVIC_SetPriority(EXTI0_1_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(EXTI0_1_IRQn);
}

_____________________________________

Since the IRQ logs output once it surely is configured correct according to me. Please point out where I am going wrong that the interrupt never happens and tag doesn't get activated for reading it.

Thanks & Regards

[Ulysses HERNIOSUS · Accepted solution]

Hi, 

please enable ST25R_SELFTEST and see if  your code still passes the initialization. Then if you still have issues, then please do a logic analyzer trace (SPI+IRQ) and post it here.

Please also be aware that the ISR as used by default in RFAL merely reads the interrupt status register. Follow-up work is to be performed by the rfalNfcWorker() and rfalWorker().

BR, Ulysses

[Atomic1]

Hello,

During ST25R_SELFTEST I noticed that it was still waiting indefinitely for an interrupt. Apparently I had set the IRQ Pin to PA0 and initialized the mode and Pull incorrectly to check for Falling edge with no pull. It worked once I changed it to:

GPIO_InitStruct.Pin = GPIO_PIN_0;

GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING;
GPIO_InitStruct.Pull = GPIO_PULLUP;

HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

HAL_NVIC_SetPriority(EXTI0_1_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(EXTI0_1_IRQn);

as mentioned in the documentation. With my previous configuration, it was waiting infinitely for the falling edge which never occurs.

Thanks