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Altera_Forum's avatar
Altera_Forum
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12 years ago

Is it save to use the PIO in QSYS

Hello, I have several PIOs in my QSYS design to communicate with some of my own designed IPs. My IPs mostly use other clock signals than the PCIe-Clock and are therefore not synchronized to t...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

OK, I see the discussion leads to a wrong direction:

My question was NOT about "How to implement an IP which counts Pulses".

I asked "Is it save to use PIOs? So let's get back to that now. Is it possible that a Altera PIO can read in values which are currently changing.

I made a testdesign which switches rapidly between two values (0xAAAAAAAA and 0x55555555) and I read them out via "PIO -> Avalon -> PCIe" as fast as I can.

But since I started my testsoftware, there were NEVER a corrupt Value like 0xAAAAFAAA or 0x55155555.

This lets me think that the Values on the PIOs are reliable. BUT WHY? Does Altera make sure somehow that no Data are read in which are currently changing?

Since now I read the PIO about 40 Billon times and there was never a failure in the Datas (Great!!!!). BUT WHY?