Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
19 years ago

PIO communication between software and hardware

I have a system I'm attempting to build that needs to transfer data between the C software and the verilog HDL. I was attempting this using bidirectional PIOs. Now if I understand these correctly...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
19 years ago

Output only PIOs have write-only data registers. I'm betting this is the source of your confusion.

[EDIT]: Oops! Just saw that you're using bidi PIOs. The following equation determines what's read...relative to the base address for the component:

<div class='quotetop'>QUOTE </div>

--- Quote Start ---

assign read_mux_out = ({1 {(address == 0)}} & data_in) |

({1 {(address == 1)}} & data_dir);[/b]

--- Quote End ---

So you&#39;re in the same boat. You cannot read what you&#39;ve just written, without some more hardware work.

Cheers,

- slacker