Hello,
I just got a new SDS 1202X-E oscilloscope (OS) and I think I found a bug in the I2C triggering system. I wonder what other users of this particular OS think about this problem.
My OS runs v.5.1.3.13 firmware and has 0c-01 hardware version. I want to trigger on "7 bit Address& Data". I properly set up the triggering on "Start" condition and can observe, decode and examine the data exchange between i2c master (AVR, hardware i2c) and slave (LCD display, addr 0x3F). The data exchange is 99% constant, always start from writing 0x8C into the slave device:
SDS00003.png
I change the triggering mode from "Start" to "7 bit Address& Data" and set the I2C address to 0x3F and any data (0xXX)- trigger works fine:
SDS00005.png
Now I set the I2C address to 0x3F and the fist byte to 0x8C -trigger does not work:
SDS00008.png
But at the same time if I set the first byte to 0 the trigger starts working:
SDS00009.png
and this is wrong.
Regarding the spikes on the SDA line - you can safely ignore them.
Thanks!
PS: this is my first post so please forgive me for not inserting the images right in the message body since it would be much easier to read the post - I simply could not figure out how to do that because the image tag could not display the images (in png format) stored on the remote ftp.
Can you be sure about the spikes ? Did you set the thresholds above them ?
Copy the image URL after posting, then Use Modify post and paste it within your text. Highlight it and use the Insert Image icon on the posting page.
BTW, is there any place where I can check for firmware updates for this o-scope? I heard about Facebook but I don't have an account and don't want to create one. I checked Siglent website and could not find any firmware updates for this device at all.
I think I found the webpage with firmware updates for this o-scope:
http://www.siglent.com/ENs/prodcut-gjjrj.aspx?id=1909&tid=1&T=2
What is really confusing is that Siglent says "SDS1000X-E " and means "SDS1202X-E" - those numbers dont match.
Give this thread a bit, member Performa01 will enlighten us to the current I2C bug situation and no doubt he's reported this one.....he don't miss much.
What I can say right now is that the before mentioned issues are mostly for LIN, SPI and UART, whereas I2C and CAN work pretty good even with the current firmware.
I happen to have a screenshot from my initial evaluation for I2C, where I can demonstrate the serial trigger working just fine.
Should the decoding start from the line 2 ?
Thanks for the screenshot. There are many factors which may affect the result i.e. why it worked for you and does not work for me. For example the version of the used firmware (mine is the latest), different hardware and such.
The I2C setup is pretty simple on this o-scope so I am 100% sure everything is done correctly during my test.
Looking at your screenshot I am curios what those "~A" characters at the of each data string means. I don't see them on my screenshots. But assuming that "A" stands for acknowledgement the situation is even more weird.
...
PS: I am not sure why I see on your screenshot the first record in the table with decoded data: your trigger is set up to trigger on writing bytes 0x89 & 0x9A to a slave with address 0x2. First record means reading from the slave with address 0x4 several bytes which have nothing to do with 0x89 & 0x9A. Should the decoding start from the line 2 ?
Apart from all that, I have no idea why the data trigger appears to fail in your setup. Maybe there actually is a bug in the SDS1202X-E that has been corrected for the SDS1x04X-E already. I would check that for you, but can do that only at the weekend, as I have no access to my lab during the week.
The “~A” character at the end of the decoded data strings actually means No Acknowledge. However, the current I2C decoder has a known bug; it might misinterpret the last acknowledgement at the end of a longer message as “no acknowledge”. We haven’t seen this bug with single byte messages yet and your decoding looks as it should. The acknowledgement in your messages is indeed correctly recognized by the scope.
It depends on the trigger position how many messages
My screenshot is from the latest (currently one and only) firmware V7.6.1.12 – this information doesn’t help much as the firmware for SDS1x04X-E has lots of additional features, hence version numbers are quite different to the SDS1202X-E.
Not sure what you mean by "averaging trigger mode".
Data Length Trigger works with the length of Address and Data in bits. This trigger obviously is only useful in a system with mixed message formats, where you want to trigger any messages that fit the format you've set for the decoder. Not sure how often this will see use in real applications - at least I for one have never seen let alone designed such a mixed format system on a single bus. This makes only sense for a multi-master system, which I've always tried to avoid at all costs.
Regarding the differences between SDS1202X-E and SDS1x04X-E you might want to have a look here:
https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/
But your specific questions are not explicitly answered there, so here is what I can tell:
A lower input capacitance is always nice of course, but 15pF vs. 18pF really doesn't make a noticeable difference in practical terms.
SDS1x04X-E scopes never had missing caps, because that problem was discovered before the first production units of this scope have left the factory.
The "E" in X-E stands for Economy. These are entry level scopes - albeit rather capable ones. But they don't feature an internal 50 ohm termination like the 1000X (without the “-E”) and 2000X do. In my review I have closely examined the input impedance of the SDS1104X-E with external termination.
The "E" in X-E stands for Economy.
I have already returned SDS1202X-E and waiting for an answer from the seller regarding availability of 1204X-E, they have to contact Siglent first.
I would say that SDS1202X-E fits my hobbyist's needs almost perfectly but I do want to have 4 channels ( I will also get wifi adapter and the software to control the device from PC) -I realized that only now.
Yes, I noticed that when I was running the built-in keypad test (you press a button and check its response on the o-scope screen) - on my 1202X-E some buttons required multiple presses. One of those buttons was single trigger and it was kind of annoying. But like you said "E" stands for economy . Other than that - I really liked this o-scope!
I have already returned SDS1202X-E and waiting for an answer from the seller regarding availability of 1204X-E, they have to contact Siglent first. I would say that SDS1202X-E fits my hobbyist's needs almost perfectly but I do want to have 4 channels ( I will also get wifi adapter and the software to control the device from PC) -I realized that only now. I have a standalone logic analyzer but after playing with serial decoding on 1202X-E I decided that it has its own merits - I think there will be times when I use the oscilloscope rather than the logic analyzer for decoding those protocols (but not always). That is why I decided to upgrade. I am also considering 2204X since its nice to have higher time sampling rate (2 vs 1 GSa/s) and more memory but in Canadian dollars it is around 3K while SDS1202X-E is 1K CAD.
Yes, I noticed that when I was running the built-in keypad test (you press a button and check its response on the o-scope screen) - on my 1202X-E some buttons required multiple presses. One of those buttons was single trigger and it was kind of annoying. But like you said "E" stands for economy . Other than that - I really liked this o-scope!
The WiFi dongle is a TP Link TL-WN725N, gold version and more cheaply available from other sources than Siglent. You'll still need the 'WiFi software enable' option: SDS1000X-E WIFI
https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/
The WiFi dongle is a TP Link TL-WN725N, gold version and more cheaply available from other sources than Siglent. You'll still need the 'WiFi software enable' option: SDS1000X-E WIFI
Yes, indeed - TP-Link TL-WN725N Wireless N Nano USB Adapter, 150Mbps at amazon.ca is just 13$ and this is way less than 65$. But after reading the excellent 8 part review of SDS1104X-E written by Performa01 I am a bit disappointed by how little this software provides and I am not even sure that I will get the WifFi adapter.
Hi,
Yesterday I finally got my brand new 1204X-E, upgraded its firmware to X.X-20 and repeated the test. It works much better than 1202X-E, for example for the triggering condition "7 Addr&Data" it can trigger on a single byte payload when the second data byte is used for setting the mask - it never worked for 1202X-E:
Yes but that was for old v.5.1.3.13 firmware.
Did you try the new v5.1.3.17R1 firmware in 1202X-E ?
Yes but that was for old v.5.1.3.13 firmware.
Did you try the new v5.1.3.17R1 firmware in 1202X-E ?
No, I did not because I sent 1202X-E back and hope to get refund. Keeping both, 1202X-E and 1204X-E would be an overkill for me.
But I was thinking a lot about getting SDS2204 since recently it was on sale in several places (1.5K USD for the o-scope + all decoding options + MSO option)
but I did not think much about replacing 1202X-E with 1204X-E. And it was really hard to find one unless one can wait till the end of March.
Hi,
Yesterday I finally got my brand new 1204X-E, upgraded its firmware to X.X-20 and repeated the test. It works much better than 1202X-E, for example for the triggering condition "7 Addr&Data" it can trigger on a single byte payload when the second data byte is used for setting the mask - it never worked for 1202X-E:
it also works now in case of setting "data length" triggering condition.
- Data Length — When SDA data’s length is equal to the value of Byte Length and address’s length is the same as set value, the oscilloscope will be triggered. Byte length is in the range of 1 to 12 bits.
I really like my 1204X-E, it's worth troubles to travel to US, get the last unit available (thanks to Jason from Siglent) and import it back to Canada.
But I was thinking a lot about getting SDS2204 since recently it was on sale in several places (1.5K USD for the o-scope + all decoding options + MSO option) but I did not think much about replacing 1202X-E with 1204X-E. And it was really hard to find one unless one can wait till the end of March.