Dear all,
I'm having the following issue with the snapshot block: I'm trying to
control the snapshot using a trigger, so that bram is only overwritten
when the trigger has a rising edge. For this I put the snapshot block in
circular capture mode, and I connect a register to the 'trig' and 'stop'
inputs, with the stop signal one clock delayed. As I understand the
block, when I trigger the register the snapshot should start writing in
memory, because I'm activating stop right after, the memory should be
written only once. However when I test my model I get different data
every time I read the snapshot. This is a minimal example of what I want
to do:
import corr, time
import numpy as np
import matplotlib.pyplot as plt
fpga = corr.katcp_wrapper.FpgaClient('192.168.1.12')
time.sleep(1)
fpga.progdev('adc_sync.bof.gz')
fpga.write_int('snap_trig', 0)
fpga.write_int('snap_trig', 1)
fpga.write_int('snap_trig', 0) # trigger the snapshot once
for _ in range(3): # read the data three times
snap_data0 = np.fromstring(fpga.snapshot_get('adcsnap0',
man_trig=True)['data'], dtype='>i1')[:400]
plt.plot(snap_data0)
plt.show() # <- should show three overlaping lines, instead I get three
different lines
My only guess is that the snapshot_get function is actually triggering
the snapshot block, so is getting new data. Anyone have some idea of
what is going on?
Franco Curotto
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