In ScanaStudio I only see the options pull-down and pull-up as input pin configurations. I don’t see a Hi-Z option. Does this mean I’m forced to always activate probe internal resistors? If so what are the resistor values?
You’re right — when using the standard high-speed probes provided with the SP1018G, the input configuration options in ScanaStudio are limited to pull-up or pull-down. There is no explicit Hi-Z (high-impedance) mode available via software control.
The internal resistor value for both pull-up and pull-down configurations is 10 kΩ, as documented here:
SP1000G Active Probes Specifications
This might seem low compared to traditional logic probes with 1 MΩ impedance, but it’s important to note that for high-speed signals (above a few MHz), the probe’s input impedance is dominated by its capacitive and reactive behavior, not just the DC resistance. The 10 kΩ resistor mainly defines the idle state of the input and has minimal impact on the signal integrity at high frequencies.
Let us know if you’re working with a special use case where a true Hi-Z mode is critical — we may be able to suggest alternative probing strategies.
I have one case where a chip’s output signal was not visible anymore. First I thought it’s a problem of my target but then I recognized that the probe’s input was the reason which is per default set to pull-down. 10k is already in the range of a strong pull-up/down. At least for low speed applications a tri-state input configuration should be available. The target itself typically comes already with own pull-ups/downs and it’s not a good thing when the probe has such a big influence and changes the target’s behaviour. That has the potential to create “Heisenbugs”, bugs that are only present if you’re watching. 
Good remark. We’ll add this option to our next revision of the probes hardware.
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Looks like you are also working 24/7 like me 
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This is highly required in my current setup. When will the probes be available and can we exchange our bought ones?
Hello @Olaf
If you’re really in a hurry, we can offer a modified probe with 1MOhm impedance instead of 10KOhm. This can be done quickly (a couple of weeks).
Otherwize, in 1 to 2 months, we should have the next hardware revision which offers 1Mohm pull down and 10KOhm optionnal pull up.
You can send me your answer in PM or via email with you shipping address.
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