[Discuss-gnuradio] [USRP-users] Register reading from the USRP2

[Eduardo Lloret Fuentes]

Hello,

I am working with a USRP2 board and the old GNU Radio driver (not the
UHD driver) under Ubuntu 10.04. I added a module to the FGPA in the
file named u2_core.v and I defined some setting registers in order to
control it. On the other hand, in the host side, I used the poke32
method to set the values of each register.

My doubt is whether is possible or not, to read from the host the
value of a FPGA register, such as the output of my module. I thouht
that the method named peek32 could be useful but it is confusing for
me.

If I understood right the architecture, the AeMB processor loads from
the memory (defined by the memory_map.h file) the value of every
setting register via the Slave #7 (Setting Bus) and by using the
poke32 method I tell the AeMB processor (modifying the memory) what
value it has to load. Hence, the communication flows from the AeMB
processor to the registers.

My question is: Is it possible to establish the communication the
other way around? I mean, load a setting register value into the AeMB
memory so I can read it using the peek32 method.

Related to this:
 - Is there an existing example of the peek32 method usage? Not
necessarily of a setting register. From the mailing list I read:
"Readback registers are only implemented for states that we need to
readback from the device." Could someone give me an example of this?

 - The firmware file named memory_map.h refers to a logic place in the
AeMB, right? What FPGA file defines this place?

A lot of thanks for any help.

Greetings.

Eduardo.