PCIe communication / 4DSP PCIe coomunication

Dear all,

I need some help from the fellows regarding PCIe communication, desperately.
I am unable to understand the PCIe communication and receiving data through it.

I have made a string pointer to receive the data from the PCIe ( it is what I followed from the sample program of the 4DSP-3rd party kit supplier)
Now in the default design things are working properly but when I entered my peice of code I get the error which indicates
'Time out' .

What I don't understand that while communicating, why do we need the string pointer to capture data.
Is this string pointer made in the simple computer memory or some dedicated PCIe memory or memory dedicated for PCIe.


Simply put: I want to ask How computer receive/send data through PCIe (I am using c++ coding)

Bests,
Shan

do you mean you want to send number or message to the slot of the mother board ?
the slot is the place where you can insert your card,like screen card

Thank you for your reply,

What I meant is this...

The API of the 3rd party has a statement sip_ifreaddata() to perform a DMA transfer(i.e. read)... Now I don't understand from where does this DMA starts... I have no clue
i.e. I am unable to understand 'FROM WHERE' is it reading....? Is it internal memory or PCIe memory...

Well let me tell you one more thing that I am assigning a string pointer as well...

And I think that data or dma transfer is stored in this string pointer.

My FPGA program is not performing well and I think this problem has a major part, if I get to understand this thing I think a good part of my problem is realized, then the second
part is solution where I can then proceed.

I hope you understand what I want to describe... I hope you guys can help me out... I can elaborate more if I am not clear.

Bests,
Shan