Interrupt-driven SPI?

Altera_Forum · ‎05-26-2010

Hi.

I'm using uC/OS-II (version 2.77) on Nios II platform using Quartus 6.0, Service Pack 1.

The SPI included provides a HAL interface that is pretty much limited to the alt_avalon_spi_command() function. This function does not give up control so other processes can run while waiting for transfers to complete.

I have attempted to use the IRQ given to the SPI Bus device in system.h, but the interrupt never seems to fire even though data is being transferred. Do I have to do something other than the following?

alt_irq_register( SPI_BUS_IF_IRQ, (void *)NULL, handle_spi_interrupts );

Thanks,

Bob.

Altera_Forum · ‎05-26-2010

You also need to write the SPI controller's "control" register to enable the interrupt.

Altera_Forum · ‎05-26-2010

Thanks. I forgot to mention that I am also doing this in my SPI access function:

IOWR_ALTERA_AVALON_SPI_CONTROL( SPI_BUS_IF_BASE,

ALTERA_AVALON_SPI_CONTROL_SSO_MSK ||

ALTERA_AVALON_SPI_CONTROL_IRRDY_MSK );

The inclusion of the ALTERA_AVALON_SPI_CONTROL_IRRDY_MSK seems to make my code always read 0xFF from the RxData register.

Thoughts?

Altera_Forum · ‎05-31-2010

Found the problem. I used logical OR (||) instead of bit-wise OR (|) in my IOWR_ALTERA_AVALON_SPI_CONTROL() call.

Thanks.