Hi Andres,
From your screen-shots
https://drive.google.com/file/d/0B9LbvB1SpcjOLXpfV0pLSzdVblU/view?usp=sharing
Your are writing the data into the BRAM as "Ufix64" (512*4) * 8 bytes
but while reading the Data you are not reading it properly
data=struct.unpack('>2048I',fpga.read('bram0',2048*4,0))
try this
data=struct.unpack('>2048I',fpga.read('bram0',2048*8,0))
One more important things is please read the tut3.py Gain term has to be
adjusted for the input signal(s).
for wideband input keep full gain and for tones keep the gain low.
ref : help='Set the digital gain (6bit quantisation scalar). Default is
0xffffffff (max), good for wideband noise. Set lower for CW tones.')
https://raw.githubusercontent.com/casper-astro/tutorials_devel/master/tut3/tut3.py
cheers
Indrajit
On Thursday 20 August 2015 12:41 AM, casper-requ...@lists.berkeley.edu
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Today's Topics:
1. Re: mux with delay to pass from parallel to serial (Andres Alvear)
----------------------------------------------------------------------
Message: 1
Date: Tue, 18 Aug 2015 21:33:01 +0000
From: Andres Alvear <andres.alve...@gmail.com>
Subject: Re: [casper] mux with delay to pass from parallel to serial
To: Jack Hickish <jackhick...@gmail.com>, CASPER Mailing List
<casper@lists.berkeley.edu>
Message-ID:
<camjzfuracfru0d+xqcupacdkpzi-jhajgcdpcfsj+xmzo9q...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Indeed I've implemented a separating out and reordering in a python script,
however rightnow I just trying to get an spectrum with a quite normal value
of the noise floor and a good dinamic range.
Anyways for this spectrometer i need the bram with depth 2^11 and 32 bits
each channel because I am sending out spectrums to my PIC32 microcontroller.
I've used to recibe data with a python script as the tutorial 3:
data=struct.unpack('>2048I',fpga.read('bram0',2048*4,0))
I've implemented the delay_bram as you can see in the picture, but the
results still are the same (I've tryed with 32bits too):
https://drive.google.com/file/d/0B9LbvB1SpcjOLXpfV0pLSzdVblU/view?usp=sharing
./s12_simple_32bits_1bram.py 192.168.1.11 -g 1000 -l 65536
https://drive.google.com/file/d/0B9LbvB1SpcjOTEV4ckFuUjlTQzQ/view?usp=sharing
I have injected a -3dBm tone signal @250MHz in the Bw=500MHz, but the data
seems intractable or maybe corrupted. I've noticed that something wrong my
models experience intermittent time outs on shared bram reads with ROACH 1.
or Maybe I can not extend the write and address time? this extra time
generate bad results? Has anyone else seen anything like this?
Regards,
Andr?s
El lun., 17 ago. 2015 a las 14:52, Jack Hickish (<jackhick...@gmail.com>)
escribi?:
Hi Andres
On Mon, 17 Aug 2015 at 08:25 Andres Alvear <andres.alve...@gmail.com>
wrote:
Hello CASPER,
I am implementing one spectrometer with one Shared BRAM yellow block with
the next specifications:
1. ROACH 1
2. ADC083000: ADC0 (ZDOK0). 8 outputs per clock.
3. Bw: 500 MHz
4. N? of channels: 2048
5. One Shared BRAM with:
- Address width: 11
- Data width: 32 bits.
I've decided implement a mux with delays to pass 4 parallel streams to
serial. Finally the idea is map into memory in a correlative order from 0
to 2047.
I have attached snapshot of my simulink model and results.
https://drive.google.com/file/d/0B9LbvB1SpcjONm5WR0ZZVmRHLUU/view?usp=sharing
https://drive.google.com/file/d/0B9LbvB1SpcjOWmZ0cVdGdmRaYUE/view?usp=sharing
https://drive.google.com/file/d/0B9LbvB1SpcjONlNwVnh5Qi01clE/view?usp=sharing
As you see in the picture I am packing the 4 parallel streams in one bram
in order to unpack 2048 channels at once instead 512 per bram (I mean a
design with 4 Shared BRAM).
Does anyone know whether simulations involving the Shared BRAM yellow
block are supposed to work? I'd like to simulate the address into the
memory. I am not pretty sure about the write and read timing for Shared
BRAM.
Simulations of the shared bram should work. If you look under the block
mask, you'll see a simulation model which is just a normal bram. By default
it has latency 1, but this will increase to 2 or 3 if you turn on one or
both of the pipelining options in the shared bram mask.
Does anyone know whether theese z^-511 delays are good enough for this
kind of implementation? I'm doing something wrong?
You certainly can do it this way -- personally for large, wide delays like
you're using I would consider using a "bram_delay" block, which will delay
your data in bram rather than slices. This block is available in the casper
delays library.
For what it's worth, the shared bram will support inputs that are 128 bits
wide, so you could dispense with your serializer. In this case, you would
just concatenate the four 32 bit streams together and save them in a shared
bram with width 128 and depth 2^9 (rather than width 32 and depth 2^11). An
arrangement like this probably also makes the readout a little simpler,
since if you read the bram and interpret the contents as 32 bit words, all
your channels will come out in order. If I'm interpreting your screen shots
correctly then at the moment your storing channels 0:2048:8, then 1:2048:8,
etc, which I'm guessing your separating out and reordering in software(?).
Cheers,
Jack
Cheers,
Andr?s Alvear
Universidad de Chile
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Thanks and regards
______________________
Indrajit Vittal Barve
Engineer,
Radio Astronomy Group,
Indian Institute of Astrophysics,
Gauribidanur.
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Mobile : +91-9845432754.
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