[Discuss-gnuradio] Using the USRP2 external SRAM

[Tiago Rogério Mück]

Hi all,

I'm working on some experiments using the USRP2, and the 32 Kb available for the firmware won't be enough for my experiments. I'll need to modify the FPGA code so I can use the 1 MB SRAM for both instructions and data for the aeMB, but I'm a bit lost on how I can do this modifications.

I looked the code and came to some conclusions about what needs to be done:

1 - Change the memory map
         - Change the RAM space to 0 - 1 MB
         - Update the mapping of the buffer poll and the peripherals

 
2 - Change the logic inside the sys_ram block to forward access to addresses beyond 32 K to the external SRAM

3 - Change the ram_loader parameters so it can load the entire firmware.

Could someone tell me if I'm going to the right direction? I will be very grateful for any hint you can give me.

Thanks