This sounds like the problem we had until Matt Dexter and Dave MacMahon
determined that some KatADC registers need to be set for correct ADC
operation. Below is the python code we use to set them:
addr = [0x0000, 0x0001, 0x0002, 0x0003, 0x0009, 0x000A, 0x000B,
val = [0x7FFF, 0xBAFF, 0x007F, 0x807F, 0x03FF, 0x007F, 0x807F,
#val = [0x7FFF, 0xB2FF, 0x007F, 0x807F, 0x03FF, 0x007F,
0x807F, 0x00FF, 0x007F] # 300 MHz
#if interleaved: val = 0x23FF # Uncomment this line for
for i in range(len(addr)):
print('Setting ADC register %04Xh to 0x%04X' % (addr[i],
# Program both ZDOKs (this could be made smarter if needed).
corr.katadc.spi_write_register(self.fpga, 0, addr[i],
corr.katadc.spi_write_register(self.fpga, 1, addr[i],
Note that at higher clock speeds, the value of the second register is
changed (commented third line), as determined by Jack Hickish. If you want
more detailed information, you will have to consult these folks, but I am
optimistic that this will help you. This uses the older corr python
module, but some equivalent command to spi_write_register() must exist in
the more up-to-date casperfpga module.
On Wed, Mar 7, 2018 at 7:09 AM, 朱岩 <zhu...@nao.cas.cn> wrote:
> Hi all,
> We have encountered some issue while using the KAT-7 KatADC on ROACH2.
> Does anyone has experience in using KatADC on ROACH2 board?
> Below are what we got while test katadc on roach2.
> In attached pictures katadc-snap-r1817*.png,
> This is a simulink model built by me to capture the sampling data from
> The 2 Zdoks are all polulated with katadc board. The sampling clock is
> 1GHz and
> the input signals are all 5MHz sine wave. The FPGA clock is derived from
> It is clear that there are something wrong with ZDOK1 katadc board.
> After that, I swapped these 2 cards, all captured signal are not good this
> as seen in katadc-snap-r1807-swapped.png.
> We also tested one single board(the bad one) connected in ZDOK0. And found
> while feeding 1GHz sampling clock, the estimated fpga clock speed from
> katcp_wrapper.py:est_brd_clk() is very unstable, as seen in
> And compare to the good board, good-card-fpga-clock.png
> This suggest some clock/timing issue with these board. We also double
> check the sampling
> clock and input signal, they are all correct.
> Then I try to lower down the sampling clock, and found while the sampling
> clock is lower
> than about 950MHz, the estimated fpga clock tends to be stable, but the
> fpga clock speed
> is /2 of sampling clock, not /4, which I think it should be /4. This was
> very strange to me,
> and might be a clue for further investigation.
> Any suggestion are welcome.
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