Hi, Jay, The yellow block does indeed convert the ADC's straight offset binary (the default mode) to two's complement. If you configure the ADC to output in two's complement, then the yellow block will convert that two's complement to straight offset binary.
What is the power level of the clock you're providing the ADCs? Is it as described in: https://casper.berkeley.edu/wiki/ADC16x250-8_coax_rev_2#ADC16x250-8_coax_rev_2_Inputs Can you please send a copy of your "adc16_init.rb" command line and its output? Other things that could be interesting are the output of "adc16_status.rb -c" and "adc16_dump_chans.rb"? Thanks, Dave On May 6, 2014, at 2:22 PM, Jay Brady wrote: > Hi all, > > I'm working on getting a system up and running using the adc16x250. To get > started I've been using the sample model,ruby gem, and user guide text file > from the wiki. I've got two issues, but I don't know if the problems are in > the yellow block, the ruby control scripts or in the model. The Ruby gem was > installed from http://astro.berkeley.edu/~davidm/gems adc16 > > For my tests, I have a 200MHz clock and a simple sine wave being fed into one > of the inputs. > > Here's the two problems: > > 1. The adc16x250-8 yellow block is putting data out in the 'straight offset > binary' format. In the adc16.rb file, there is a comment that says the yellow > block should converts this to two's complement (line 290ish). Is that true, > or should I plan on the yellow block not converting it and set the adc > control reg to give me two's complement instead of the offset binary? > > 2. The data coming out of the yellow block is the same for two consecutive > clocks and it seems to skip every other sample (i.e [0 0 2 2 4 4] instead of > [ 0 1 2 3 4 5]). It seems like it's not switching between lanes A/B. > > I've looked through the adc16_init.rb, adc16_plot_chans.rb and adc16.rb > scripts and some of the yellow block vhdl, but I'm not seeing anything that > jumps out at me. Perhaps someone else knows what I need to do? > > Thanks, > Jay Brady > >
