Honored ContributorHi,
Is it possible to get SignalTap to use external memory for data logging? I got 256MByte of DDR2 memory in my NIOS system, using the Altera DDR2 memory controller. Logging traces to this memory could be usefull, when debugging slow but long signal patterns, e.g. a complete PAL/NTSC video frame signal. BR Peter
Honored ContributorHonored ContributorPeter,
I agree to pletz. As far as i know there is no way to connect external memory to signal tap. So, I would recommend that you built your own trace logic and write the data of interest into memory using a FIFO and a DMA controller.Honored ContributorDDR2 is going to have bandwidth issues. Hopefully too much, but if it's too little than the capture will fail. In-system memory works because only and exactly what is necessary will be used. More importantly, if the design had DDR2 on it, most likely the designer has their own controller and it's part of system operation(unless it's a development kit that happened to have DDR2 on it). So there's no way for SignalTap to access the DDR2 without altering the user's design.
Honored ContributorSignalTap will not do it for you.
I have written a few internal logic analyzers that made use of DDR2 memory. You can certainly do it; especially to do simple captures comparable to what SignalTap does. But of course you will have to write all of the logic (memory interface, trigger logic). JakeHonored Contributorjakobjones:
Yes, it was exactly that I wanted, captures which are of lower bandwide (compared to internal FPGA RAM), but with long sequences of signals. If Altera had/made an IP that plug'ed on to the Avalon bus as a busmaster on one side, and to "probe-signals" on the other, any free bandwide on whatever RAM on the Avalon bus that is present, could be used for logging. Doing the IP myself, will still miss the important integration with the SignalTap GUI in Quartus on the PC, so although making a FIFO+Avalon master DMA muck-up would not be a big problem, getting the data out of the RAM and presented on the PC in a usefull way would need some work, I think? Hope Altera will do such a core/GUI integration one day. /PeterHonored ContributorQuite right. For the projects I did, we also had to write the GUI.
Jake
