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Altera_Forum
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14 years ago

Nios 2 to custom component communication

Hi, I'd like to know what instructions of Nios C program Do I need for writing and reading data to/from a custom component of sopc system??? I saw in some AN people use IORD() /IOWR() macros or...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

Start with IORD/IOWR. They are fine for nearly all purposes.

Later you can add an abstraction layer if you like, but everything is managed with the same io functions at low level.

Regarding the address, you must distinguish:

base address: this is arbitrarily defined in sopc builder/Qsys

address span: the range of addresses your component is supposed to respond to, from base to base+span

register addresses: these are actual memory locations made available in your component; from offset 0 to offset address_span-1. The external bus must add the base address to the offset to access the component memory.