I2C Read/Write functions in GPIO Interrupt

Question

Hi. 
 I've configured an I2C device to gather data and if finished it will trigger an interrupt line which I connected to the an GPIO interrupt of the NRF52. I'm using i2c_burst_read(...) from within that GPIO interrupt but always get the following error: 
 
 &#160;<err> i2c_nrfx_twim: Error on I2C line occurred for message 0 
 With polling the GPIO line and then reading the data out of the I2C device everything works fine. Is there a restriction accessing I2C functions within an interrupt? How would be the solution to this? I was thinking of using an event which i set in the GPIO interrupt and in a thread I read out the data with I2C functions. But would't that be way slower that just reading a few registers within the ISR? 
 I configured the GPIO interrupt using:

gpio_pin_configure_dt(&int1, GPIO_INPUT);
gpio_pin_interrupt_configure_dt(&int1, GPIO_INT_EDGE_TO_ACTIVE);
gpio_init_callback(&irq1, int1_callback, BIT(int1.pin));
gpio_add_callback(int1.port, &irq1);

I appreciate every help. 
 
 Thanks & Best Regards, 
 Phobios

Vidar Berg · Accepted Answer

Hello Phobios, 
 
 But would't that be way slower that just reading a few registers within the ISR 
 The API initiates the read transaction and doesn't return until the transaction completes, making it more involved than reading some registers. As a result, the blocking time can be relatively long. 
 
 The i2c driver is using semaphores with waits to allow the API to be blocking/synchronous, and these cannot be called from an interrupt context. 
 
 How would be the solution to this? I was thinking of using an event which i set in the GPIO interrupt and in a thread I read out the data with I2C functions 
 If you create a separate thread, you can use k_sem_give() from the gpio interrupt to wake-up this thread and perform the burst read. Alternatively, you can create a workqueue item to read the sensor. 
 Best regards, 
 Vidar

I2C Read/Write functions in GPIO Interrupt

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