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Markgel's avatar
Markgel
Icon for New Contributor rankNew Contributor
5 years ago
Solved

inout PIO value change

Have an Avalon inout PIO register connected to PCIe Bar addr space. When changing the "in" buffer - it doesn't affect the output buffer, but if reading PIO from PCIe bar the value does changed to th...
  • KhaiChein_Y_Intel's avatar
    KhaiChein_Y_Intel
    5 years ago

    Hi Mark,


    Pertaining to the question earlier on the output buffer does not reflect the changing of the input buffer, it is an expected behavior. The hardware logic in the PIO is separate for reading and writing the data register. Reading the data register returns the value present on the input ports (if present). Writing data affects the value driven to the output ports (if present). These ports are independent; reading the data register does not return previously-written data.


    For the self clearing bit, you may select "Enable individual bit setting/clearing" when you generate the PIO IP. This option is available for the output register only. When this option is turned on, two additional registers—outset and outclear—are implemented. You can use these registers to specify the output bit to set and clear.


    Thanks

    Best regards,

    KhaiY


KhaiChein_Y_Intel's avatar
KhaiChein_Y_Intel
Icon for Regular Contributor rankRegular Contributor
5 years ago

Hi Mark,


1) Which device you are using? Are you using P-tile or L-Tile / H-tile?

2) Are you using Avalon MM interface or Avalon ST interface?

3) Is the PCIe a Endpoint or Root port?

4) Are you trying to configure the BAR address space?

5)Regarding the self clearing bit, may I know which bit is this? What is the function of this bit? Is the 'bit' in memory read/write TLP or configuration TLP?

6) It is mentioned that the PIO buffer is connected to PCIe BAR. May I know the PCIe signal name that connects to this PIO buffer?

7) PC write 1. Can you describe how does the PC write 1 and through which interface/signal? Do you mean resetting something in the PCIe?


Thanks

Best regards,

KhaiY