When I use the AXI Quad SPI in slave mode for read some data. I meet a problem, the interrupt status register of the ip core show the underrun error occured. I know it is means the master spi device read the empty fifo of the slave spi. but how to fill the fifo to solve this problem? I mean when to write the slave DTR fifo with the data? This is the first problem I met.
The other one is when I get the DRR_not_empty interrupt and read the data from the slave DRR fifo, it's ok! But when the master device transmit the data second time, the DRR fifo of the slave contains the data indeed, and the rfo register show the correct lenth. but the interrupt does not goes active to call the interrupt handler function. Only the slave selected interrupt I get! I don't know why it happen like this.
Is there any one can help me? Thank you very much!