Are SPI interrupt disabled in GPIOTE handler?

[Prasad]

I am writing code for nrf51822 with softdevice and an accelerometer is connected to the nrf chip. The accelerometer provides interrupt to nrf chip over GPIOTE whenever there is data available to read. Upon receiving the GPIOTE interrupt, I am reading accelerometer data over SPI using nrf_drv_spi_transfer() and the SPI event handler that I have written(This even handler is hit when read is completed).

Since I have 3 axis data I am calling nrf_drv_spi_transfer() 3 times from the GPIOTE handler(for reading x, y and z axis data). But the SPI even handler is never reached.

Are SPI interrupt disabled in GPIOTE handler? I have set APP_IRQ_PRIORITY_LOW to GPIOTE handler.

[Jørgen Holmefjord]

What is the IRQ priority configured for the SPI master driver? Notice the comment from the SPI driver doucmentation: "There is no context blocking in the interrupt handler. Therefore, it is assumed that the driver API will not be called from a context with higher priority than the instance interrupt, because this might cause driver failure.". If SPI driver priority is set to APP_IRQ_PRIORITY_LOWEST, you might see issues like this.

[Prasad]

I am using NRF_DRV_SPI_DEFAULT_CONFIG to initialise my SPI instance and I have set SPI_DEFAULT_CONFIG_IRQ_PRIORITY 3 in sdk_config.h I guess I need to change this and check again...

[Prasad]

Thanks Jørgen, the issue got resolved when I changed SPI_DEFAULT_CONFIG_IRQ_PRIORITY in sdk_config.h from 3 to 2. But I found this comment in sdk_config.h.

// <i> Priorities 0,2 (nRF51) and 0,1,4,5 (nRF52) are reserved for SoftDevice
// <0=> 0 (highest) 
// <1=> 1 
// <2=> 2 
// <3=> 3 

#ifndef SPI_DEFAULT_CONFIG_IRQ_PRIORITY
#define SPI_DEFAULT_CONFIG_IRQ_PRIORITY 2
#endif

Does this mean that I cannot call softdevice APIs from the SPI event handler now?

[Jørgen Holmefjord]

You should get an assert if you set the priority to one of the ones reserved for the softdevice, and SOFTDEVICE_PRESENT is defined. Did you set this priority with softdevice present?

[Prasad]

Yes, I did set the priority with softdevice present.