Simple sampling using PuTTY
Posted: Wed Sep 17, 2014 11:01 am
Could somebody please tell me what i'm doing wrong.
i am trying to sample a short pulse using PuTTY on windows 7.
I have an 80 µs pulse (to measure) with an 80 µs, 500 mV trigger pulse overlapping with it's negative edge 40 µs into the measured pulse.
I use the following commands:
redpitaya> monitor 0x40100000 0x1 - Reset write state machine
redpitaya> monitor 0x40100014 0x1024 - Set decimation to 1024 (~8 µs between samples)
redpitaya> monitor 0x40100014 - Check decimation
0x00001024 - Readback confirmed correct decimation
redpitaya> monitor 0x4010000c 0x811 - Set Channel B threshold to ~ 0.3 V
redpitaya> monitor 0x4010000c - Check threshold
0x00000811 - Readback confirmed correct threshold
redpitaya> monitor 0x40100000 0x0 - Arm trigger
redpitaya> monitor 0x40100004 0x5 - Set trigger to Ch B threshold negative edge
redpitaya> monitor 0x40100004 - Check for trigger source to go to 0 (confirmed trigger)
0x00000000 - Trigger confirmed
redpitaya> monitor 0x4010001c - Read trigger write pointer address
0x00003d34 - Address read back
redpitaya> monitor 0x40113d34 - Attempt to read value
Segmentation fault - Read failed due to segmentation
redpitaya> monitor 0x401131fc - Try again at the start of the segment
0x00002de1 - value read back as 2de1 Hex (11745 ADC value)
If i use the acquire tool with the same decimation i can see the two pulses with 10 correctly measured samples and the timing is as i see on my oscilloscope.
Am i making an obvious mistake? if i use a much longer pulse (200 µs) it seems to work.
Thanks in advance
Steve
i am trying to sample a short pulse using PuTTY on windows 7.
I have an 80 µs pulse (to measure) with an 80 µs, 500 mV trigger pulse overlapping with it's negative edge 40 µs into the measured pulse.
I use the following commands:
redpitaya> monitor 0x40100000 0x1 - Reset write state machine
redpitaya> monitor 0x40100014 0x1024 - Set decimation to 1024 (~8 µs between samples)
redpitaya> monitor 0x40100014 - Check decimation
0x00001024 - Readback confirmed correct decimation
redpitaya> monitor 0x4010000c 0x811 - Set Channel B threshold to ~ 0.3 V
redpitaya> monitor 0x4010000c - Check threshold
0x00000811 - Readback confirmed correct threshold
redpitaya> monitor 0x40100000 0x0 - Arm trigger
redpitaya> monitor 0x40100004 0x5 - Set trigger to Ch B threshold negative edge
redpitaya> monitor 0x40100004 - Check for trigger source to go to 0 (confirmed trigger)
0x00000000 - Trigger confirmed
redpitaya> monitor 0x4010001c - Read trigger write pointer address
0x00003d34 - Address read back
redpitaya> monitor 0x40113d34 - Attempt to read value
Segmentation fault - Read failed due to segmentation
redpitaya> monitor 0x401131fc - Try again at the start of the segment
0x00002de1 - value read back as 2de1 Hex (11745 ADC value)
If i use the acquire tool with the same decimation i can see the two pulses with 10 correctly measured samples and the timing is as i see on my oscilloscope.
Am i making an obvious mistake? if i use a much longer pulse (200 µs) it seems to work.
Thanks in advance
Steve