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Re: [Discuss-gnuradio] transmission buffer
From: |
ldoolitt |
Subject: |
Re: [Discuss-gnuradio] transmission buffer |
Date: |
Thu, 12 Oct 2006 08:05:58 -0700 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
On Thu, Oct 12, 2006 at 12:10:23AM -0700, Oussama Sekkat wrote:
> One of the input to the usrp_std module is SDI. From my understading, a
> serial address and serial data is sent through that input in order to
> control registers inside the FPGA. What I don't know is the origin of the
> input. It doesn't seem to be coming from the GPIF bus.
> How is the SDI signal sent from the USB to the FPGA?
The 8051 bit-bangs the SDI data, clock, and strobe lines.
They are "slow" compared to other FPGA actions.
See usrp-*/firmware/src/usrp1/spi.c
- Larry