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Altera_Forum
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15 years ago

Programming IO ports in NIOS II

Hi, Im new to nios ii software programming.I need to implement a hardware on an fpga.But as there are no sufficient pins availabile on the board,i thought of using a nios 2 processor to give external...
Altera_Forum's avatar
Altera_Forum
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15 years ago

PIO ports are memory mapped.

For a PIO input you check the bits corresponding to the input you want to test.

For a PIO output you change the bits.

Nios tools provide some macros to easily work with PIOs.

Say PIO_BASE is base address (assigned in sopc builder) of a 16 wide PIO output port;

this will set high outputs 2,5,6,7,8,12 of a 16

IOWR_ALTERA_AVALON_PIO_DATA(PIO_BASE, 0x10F2);

Similar for an input port. This will test if input 6 is high:

if (IORD_ALTERA_AVALON_PIO_DATA(PIO_BASE) & 0x0040) ....