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USB Superspeed Peripherals

New Contributor II

Hi All,

     I am designing a simple project which writes a 16 bit data and reads from my application board.

I have built custom Board using FX3 and Spartan FPGA 6.

Iam able to do the boot loading firmware.

As a firmware for FX3 using SyncSlave FIFO image.

Just modified few things : changed to 16bit Databus and Buffer count as 1 from 2.

In GPIF iam using Flagc as dedicated thread 3 for FPGA reading from FIFO.

Right now iam not writing anything into FIFO(no FPGA Logic Made).

Iam using USB Control Centre to  Data ut just 2 BYTE (16bit)  and see my FlagC is Showing after reading 2 Cycles (along with recommended latency).

But my FLAGC always in High. its not going low. Data also not coming from Buffer.

Could Somebody get me a help out this it will be gratefull.

Please.  Thank you

Rgds,

Muthu.

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Moderator
Moderator

Hi Muthu,

FLAGC only goes low whenever there's some data in the buffer indicating that the buffer is not empty and has some data that the FPGA can read.

So, in order for the FPGA to read data, the buffer should contain some data after every read from the buffer.

When there is some data, FLAGC will again go low indicating not empty and the FPGA can read the data again.

So, You need to send continuously 2Bytes of data after every read so that the FLAGC behaves as expected.

Regards,

Yashwant

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Moderator
Moderator

Hi Muthu,

FLAGC only goes low whenever there's some data in the buffer indicating that the buffer is not empty and has some data that the FPGA can read.

So, in order for the FPGA to read data, the buffer should contain some data after every read from the buffer.

When there is some data, FLAGC will again go low indicating not empty and the FPGA can read the data again.

So, You need to send continuously 2Bytes of data after every read so that the FLAGC behaves as expected.

Regards,

Yashwant

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New Contributor II

Dear Mr.Yashwant,

     Thanks for Checking Up. Sorry I couldn't Update due to shot on-site Visit.

The issue was due not configured the FLAGs properly in GPIF. Now Issue is Solved. Thanks for your help.

Rgds,

Muthu

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