Re: [Discuss-gnuradio] USB Issues

[Eric Blossom]

On Tue, Jan 17, 2006 at 06:10:43PM -0500, Brian Dunn wrote:
> Hi Eric -
> 
> I've taken a guess at what needs to be done to look at the RD and WR  
> signals needed for USB debugging.  If I'm way off, could you point me  
> in the right direction?  The two main questions I have are

> 1) What do we give u._write_oe(...)? I'm guessing  your "be careful"  
> was referring to making sure we don't enable outputs that are  
> connected to another IC as outputs, PWR, or GND.

"be careful" just means be sure you've got basic tx and rx boards
connected.  

  u._write_oe(0, 0xffff, 0xffff)

> 2) How does the verilog (.v) get compiled?  Do we need a separate  
> utility to do this or does rebuilding /usrp do this automatically?

We use the free (beer) Quartus II Web Edition tools available at
www.altera.com.  They only run under Windows.  If this is a pain, just
say so and I'll build the FPGA image for you.


> Here's my attempt:
> 
> In /usrp/firmware/include/fpga_regs_common.v change
> `define FR_DEBUG_EN               7'd14
> to
> `define FR_DEBUG_EN               7'd15
> so that all 4 daughter cards i/o pins are controlled by the FPGA.  
> (7'd15 = b0001111)

Not quite.  The FR_* defines are the register number definitions.
Don't change anything there.  We just set the register value from python:

from usrp_fpga_regs import *

u._write_fpga_reg(FR_DEBUG_EN, 0x0003)   # enable debug output on TX_A, RX_A


> In /usrp/fpga/toplevel/usrp_std/usrp_std.v change
> .debug_0(rx_debugbus),.debug_1(ddc0_in_i),
> to
> .debug_0(rx_debugbus),.debug_1(tx_debugbus),
> so that tx_debug (contains WR) is also available on a daughter card.

> Assuming (?):           >>>     Yes, this is correct

> .debug0 -> TX_A   
> .debug1 -> RX_A
> .debug2 -> TX_B
> .debug3 -> RX_B,
> 
> TX_A header will be rx_debugbus defined in rx_buffer.v as:
>    assign debugbus[0] = RD;
>    assign debugbus[1] = rx_overrun;
>    assign debugbus[2] = read_count[8];
>    assign debugbus[3] = rx_full;
>    assign debugbus[4] = rxstrobe;
>    assign debugbus[5] = usbclk;
>    assign debugbus[6] = have_pkt_rdy;
>    assign debugbus[10:7] = store_next;
>    assign debugbus[15:11] = bitwidth;
> 
> RX_A header will be tx_debugbus defined in tx_buffer.v as:
>    assign debugbus[0] = WR;
>    assign debugbus[1] = have_space;
>    assign debugbus[2] = tx_empty;
>    assign debugbus[3] = tx_full;
>    assign debugbus[4] = tx_underrun;
>    assign debugbus[5] = write_count[8];
>    assign debugbus[6] = txstrobe;
>    assign debugbus[7] = rdreq;
>    assign debugbus[11:8] = load_next;
> 
> In benchmark_usb.py enable the outputs by adding
> u._write_oe(...)

Yep.  You'll need:

from usrp_fpga_regs import *

usrp_rx._write_fpga_reg(FR_DEBUG_EN, 0x0003)   # enable debug output on TX_A, 
RX_A
usrp_rx._write_oe(0, 0xffff, 0xffff)           # make all pins output from FPGA
usrp_tx._write_oe(0, 0xffff, 0xffff)



> Compile the verilog?

Fire up Quartus then "File / Open Project".  The file you're looking
for is in usrp/fpga/toplevel/usrp_std

Once the project is open, press the button on the button bar that looks
like the tape recorder "Play" symbol (the right-facing triangle).
Wait 20 minutes.  Enjoy.

Copy output file usrp_std.rbf to <prefix>/share/usrp/rev2/usrp_fpga.rbf

> Rebuild /usrp and then run modified benchmark_usb.py

Shouldn't have to rebuild usrp.  Just rerun the benchmark.

> Thanks,
> Brian

Eric