Hi all
I've had a RedPitaya v1.1 in my drawer for a couple years, and recently dusted it off, upgraded to the current FW (details as reported in the bottom right of the main screen are "Red Pitaya OS 0.98-694 / STEM 14") to do some SPI debugging using the GPIO interface. For some reason, the logic signals are all inverted in the Logic Analyser app. I feel like I'm going insane, but I've checked it from all angles, and cannot see what I'm doing wrong.
As a test, I've set up a simple flashing signal from an STM32 Discovery board 100ms on, 200ms off. When measure with the oscilloscope, the signal is as I expect to see it.
However, when I have connected the GND to E1:pin 25 and the flashing signal to E1:pin 3, the logic analyser shows the signal as high when at 0V, and low when the signal is 3.3V.
Am I going mad?
Thanks
Etienne
Digital IO Inverted
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- Posts: 4
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Digital IO Inverted
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- Posts: 4
- Joined: Thu Oct 22, 2015 2:17 pm
Re: Digital IO Inverted
I figured it out eventually... The original v1.1 is now the Stem125-14, which doesn't support this mode as it's configured with differential inputs, and the logic is inverted. Unfortunately, the allowed voltage bands for a logic 1 and 0 don't allow me to simply connect the one side to 3V and use the other side for the probes.
However, there's nothing here that an AM26LV31EIDR can't fix
However, there's nothing here that an AM26LV31EIDR can't fix
- redpitaya
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Re: Digital IO Inverted
Hi and thank you for posting.
You were not using the add-on Logic analyzer PRO hardware module, right??
https://www.redpitaya.com/Catalog/p14/l ... ro?cat=c97
You were not using the add-on Logic analyzer PRO hardware module, right??
https://www.redpitaya.com/Catalog/p14/l ... ro?cat=c97
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