Rigol MSO5074 trigger time delay - Page 1
Forum section: electronics / testgear

author: listerreg
author_rank: Newbie
timestamp: November 21, 2023, 09:32:43 pm
content: Hi,I have this I2C scenario. Master sends some data to the slave, waits, sends some more data, wait longer and receives data.How to capture the receiving part?I thought that I’ll just set the time delay after triggering on the start of the sequence and that’s it, but after few hours of searching I’m starting to suspect that this is not possible with this model…Could it be true that such simple feature is missing in this oscilloscope?I can trigger on Nth edge but it is tedious and error prone to count them all.ThanksP.S. I don’t want to use protocol decoding.

author: thm_w
author_rank: Super Contributor
timestamp: November 22, 2023, 12:04:45 am
content: Does this sequence happen once or multiple times repeatedly? If its once you can: capture a large period of time then zoom in, use high holdoff time, or use a delay trigger.Why don't you want to use protocol decoding?Usually for this scenario a PC based USB logic analyzer which can be had for ~$10 works quite well.

author: 2N3055
author_rank: Super Contributor
timestamp: November 22, 2023, 11:24:10 am
content: Quote from: listerreg on November 21, 2023, 09:32:43 pmI find it hard to believe it is not possible.On all the scopes I ever used, you set trigger settings and get stable trigger. And then with horizontal position setting you set the scope to show you part of signal 1 ms (or whatever period within specifications) after trigger event.

author: ebastler
author_rank: Super Contributor
timestamp: November 22, 2023, 04:32:23 pm
content: Quote from: listerreg on November 21, 2023, 09:32:43 pmThat's exactly how I would expect it to work -- assuming that there is a constant delay between the initial message sent by the master and the response by the slave.Which part of this approach did not work for you? I don't have the MSO5000, but going by the way other Rigol scopes handle this, can't you just set the desired trigger, then shift the trigger point way to the left via the Horizontal Positon knob? Or enable Zoom mode to get a better overview where you are in time, then shift the zoomed-in view to the desired position.(Note that this delay is not set in the trigger menu, but is a feature of the Horizontal section.)

author: listerreg
author_rank: Newbie
timestamp: November 23, 2023, 10:19:08 pm
content: Thanks for all the answers!Sorry, I didn’t make myself clear. I just assume there will be an “option” to set arbitrary delay since I need more than 1 second of this delay and that is all I’m getting from turning the knob.Maybe I just don’t get it how it is a technical limitation not to let this delay to be any period.Anyway, now I know I can stop searchingGreets

author: ebastler
author_rank: Super Contributor
timestamp: November 24, 2023, 12:47:27 pm
content: Quote from: listerreg on November 23, 2023, 10:19:08 pmIs that a fixed limit, or is it relative to the timebase? I.e. can you get a larger delay if you go to a slower ms/div setting? To make the decoded messages readable, you might need to zoom in then -- either via Zoom mode, or by stopping the acquisition and switching to a faster timebase afterwards.