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Re: [Discuss-gnuradio] Using the USRP2 external SRAM
From: |
Eric Blossom |
Subject: |
Re: [Discuss-gnuradio] Using the USRP2 external SRAM |
Date: |
Mon, 15 Jun 2009 07:10:13 -0700 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
On Wed, Jun 10, 2009 at 04:59:24PM -0300, Tiago Rogério Mück wrote:
> 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.
Yes, this is the right direction. You'll probably want to include a
dcache to get any kind of throughput out of it. There's currently a
small icache.
Eric