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1. 

   richiereynolds
   Member

   Hello, I'm using the maple as a slave SPI receiver. I want to trigger an interrupt routine when data is received but can't quite work out how to do it, can anyone help?

   I've done this:
   
HardwareSPI(2) spi;
setup()
{
spi.beginSlave();
spi_irq_enable(SPI2, SPI_RXNE_INTERRUPT);
}

   void handleSpi()
{
byte b = spi.read();
...
}

   So my question is how do I set up my handleSpi as the interrupt handler?
   In the header files I've traced through and found that the nvic_irq_num for SPI2 is NVIC_SPI2 = 36 but I don't know how to use that to set up an interrupt. Is that even relevant?

   Thanks for any help!

   Posted 3 years ago #
2. 

   mbolivar
   LeafLabs

   hi,

   calling spi_irq_enable() as you have done enables both the interrupt line (in the NVIC) and the SPI RX not empty interrupt. however, the vector table entry for SPI2 doesn't point to anything useful by default, as libmaple doesn't (currently) provide an interrupt handler for the SPI peripherals. as you guessed, you need to register an interrupt handler yourself. you can do this by declaring a function named __irq_spi2, with C linkage, like so:

   extern "C" void __irq_spi2(void) {
       // your SPI2 handler code goes here
   }

   the linker looks for a function with this name, and will cause it to be used as the SPI2 IRQ handler if it's defined. note that the extern "C" is mandatory -- you must give this function C linkage, or its name will go through C++ name mangling, and the linker won't pick up on it.

   hope this helps!

   Posted 3 years ago #
3. 

   richiereynolds
   Member

   Thankyou very much, works a treat!

   Posted 3 years ago #
4. 

   phisatho
   Member

   Shouldn't this be added to Wiki?

   Posted 3 years ago #

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