Author Topic: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004  (Read 440311 times)

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Offline AlexFerro

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Re: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004
« Reply #2625 on: November 16, 2019, 09:36:55 pm »
I have a couple of feature requests for the I2C Decoder/Trigger. I hit some cases at work debugging an I2C bus that I couldn't just set a trigger on. I actually hit these on the RTM3004 at work, but I just checked my RTB2004 and the feature appears to be common, so I chose to post here since it's a more active thread.
I have no idea how feasible these are, just that I hit on them while debugging a troublesome I2C bus.

The first feature is related to the "Trigger on NACK" which I have found very useful in the past for debugging unexpected transaction failures, but this bus also has read traffic, where a NACK is a normal occurrence, and so the scope just triggered on every read transaction, hiding the failed write transaction in all the other triggers.
At a minimum I'd love a "Trigger on unexpected NACK" that would ignore the normal NACK at the end of a read cycle that is immediately followed by a stop condition. Although that brings up the idea that an "Unexpected ACK" trigger might be useful to trigger when the master fails to perform the spec required NACK at the end of a receive. An even more useful NACK trigger would include the above, but allow it to be filtered by address, so that a system containing a device that intentionally NACKs its address, like an EEPROM that is still busy writing, could be ignored by filtering for the other device you are having trouble with.

The second I2C trigger is a modification of the address and data trigger, to include being able to select trigger on an address only and zero data bytes. The suggested work around of setting a single byte trigger with all don't care bits does not cover the case of a system either getting a NACK and giving up without sending data, or simply a protocol error where the address is sent, but a stop condition is generated. I ran into this when I couldn't trigger on just the specific NACK, but I knew what address the issue was and thus tried to trigger on any access to that device to see if there was an analog issue during access to it causing the problem.

I hope these are feasible and I'm not the only person who thinks these would be useful. Although if I have just missed how to do these, I'd love to be corrected, but I could not find a way to do this (other than hacking out most of the complex system code to not do any other operations that trigger the scope).
Typos and other errors graciously sponsored by my brain and/or the time of day.
 

Offline Hydron

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Re: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004
« Reply #2626 on: November 17, 2019, 06:26:28 pm »
I'll check.  Anything in particular you want me to check on?

-Rich
Hi Rich,

If the firmware guys need suggestions for improvements, other than the previously discussed questions about FFT buffer size management (e.g. my comment here: https://www.eevblog.com/forum/testgear/new-killer-scope-a-true-game-changer-from-rs-rtb2002-rtb2004/msg2693064/#msg2693064), would it be possible to extend the bandwidth limit function to support cut-off frequencies other than 20MHz and full BW?
Sometimes it's nice to bandlimit a signal (e.g. to reduce noise) but 20MHz isn't the best option - allowing for it to be limited to one of the lower end options offered for the same instrument (i.e. 70/100/200MHz for a 300MHz optioned RTB2k) would be very handy, and I assume the scope is even already calibrated for these steps to support the option system. It looks like something like this is offered for the RTM3k series - is this a market segmentation thing, or just a feature that was added after the RTB2k was already done?
 

Offline KaneTW

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Re: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004
« Reply #2627 on: November 17, 2019, 06:36:36 pm »
I hope Munich reevaluates the market segmentation, or at least offers a discounted upgrade path to the RTM series.
 

Offline Rich@RohdeScopesUSA

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Re: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004
« Reply #2628 on: November 18, 2019, 02:40:52 pm »
Thanks everyone for the notes - I'll make sure Munich gets this feedback.

-Rich
 
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Offline egonotto

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Re: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004
« Reply #2629 on: December 03, 2019, 05:08:22 am »
Hello,

I wonder the R&S®RTB2004 has input impedance "1 MΩ ± 2 % with 9 pF ± 2 pF"
while the RTO2000 has "1 MΩ ± 1 % || 15 pF"
and the RTM3000 has "1 MΩ ± 1 % || 14 pF ± 1 pF".

Why has the lower frequency scope so much better input impedance?

Best regards
egonotto
 

Offline Joel_l

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Re: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004
« Reply #2630 on: December 05, 2019, 02:29:40 am »
I'll take the opportunity to plug a request again,

An event A followed by an event B trigger, channel and pattern. Maybe the same or related to the edge A/B request below.

Thanks Rich,

Joel

Hi all,


- new Trigger types: Runt, Rise time, Edge A/B
  (here I contacted already R+S Munich and I have got a feedback: reserved for RTB3000...
   sorry, but all other 400,-€ scopes can do this...)



 

Offline Rich@RohdeScopesUSA

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Re: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004
« Reply #2631 on: December 05, 2019, 06:52:00 pm »
I'll take the opportunity to plug a request again,

An event A followed by an event B trigger, channel and pattern. Maybe the same or related to the edge A/B request below.

Thanks Rich,

Joel

Hi all,


- new Trigger types: Runt, Rise time, Edge A/B
  (here I contacted already R+S Munich and I have got a feedback: reserved for RTB3000...
   sorry, but all other 400,-€ scopes can do this...)



Thanks.  I'll make sure Munich hears this again. 

And just an update on the next RTB2000 firmware.  No firm date, but one is in progress.  As I get more details I'll post them up.

-Rich
 


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