DMA FIFO

[Intaris]

Is it FPGA, is it NI Hardware? Is it PXI? is it USB?

You're gonna have to tell me SOMETHING if you want help.......

Maybe it's a blackboard and you need some chalk? I can't know if you don't tell me anything.....

Shane

[RedAG]

No, it's not FPGA, not an NI hardware, not a PXI or a USB.

It is a device that performs its own function, circuit testing to be precise among others. 

Actually, I want to read in how this process is done by reading in the digital signals while its circuit testing and then send back a signal/signals (to a memory device which is being circuit tested by the tester) back to the device (based on the signals first obtained from teh circuit tester), therbey in turn writting to that memory.

To break it down - Circuit Tester is circuit testing. I read in while its doing so, write back to the device it is circuit testing.

Let me know if you need further clarification.

[Intaris]

I have absolutely no idea what you are talking about.

Sorry.

[crossrulz]

How are you connected to this super secret device?  Unless drivers are given for it with DMA access, I doubt you can use DMA.

[RedAG]

Intaris and crossrulz, sorry for all the confusion.

Basically, this is what I want to do: There is a third party circuit tester (Device 1) which tests the circuit and resets the memory of other devices (Device 2). I want to read in while Device 1 and Device 2 are communicating (Particulary while reseting). When reading in, I will be dealing with signals coming from this communication that I have no idea about. The only information I can think of is in patents and I have searched a lot and what I understand is that, there would be between 4 and 6 signals. They could be a Clk, Rst, Data. To analyse this signals, I would need to build a Logic Analyser Vi and then after analysing this signals, I want to alter the one of the signals and send it back to Device 2. In a way, fooling the Device 2 into thinking the data coming from is from Device 1.

Phew. Now, I have managed to read in a single digital pulse so far. Now, I want to test if I can send data back, which is why I need to know about the DMA and whether it should be used for transfer back to the FPGA from the HOST and then from teh FPGA to the Device 1 Device 2 communication. 

[Intaris · Accepted solution]

It's slightly clearer now.

You're communicating over digital lines with both external devices, right?

To get the signals you want to send to the FPGA from your Host, you will need DMA, that much is clear.  A DMA Channel is unidirectional meaning you need to set up one for FPGA-Host and one for Host-FPGA.

Shane.

[RedAG]

Thanks Shane.

Well, not exatcly to both devices, but to Device 2 in particular, therby over riding the signal the Device 1 want to send to Device 2 with my signal.