Another DSO+DMM - Zeeweii DSO3D12, claimed 120MHz/250MSps (june 2023)

[motoge]

Answer from ZEEWEII

Hello,
Since such waveforms are actually debatable, I recommend using cursors for measurements. Press "Shift"->"s" to open the time cursor.
For example, in the image below, it is hard to determine whether the negative pulse width is A or B. With an oscilloscope, it is really hard to judge.
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[LucSVK]

Hello Guys,
  Please, do you have any Hi-Res pictures of the device's PCB?

Thanks a lot!

[wasedadoc]

Hello Guys,
  Please, do you have any Hi-Res pictures of the device's PCB?

Thanks a lot!

At least one of the YT reviews linked in posts above has good views of the internals. https://www.eevblog.com/forum/testgear/another-dsodmm-zeeweii-dso3d12-claimed-120mhz250msps/msg5274556/#msg5274556

[LucSVK]

Hi, I have seen the reviews but unfortunately it isn't enough.

I would like to see what is connected where and gather as many information/datasheets as I can.

I wonder if they even are able to implement USB/OTG or any other high speed communication + other stuff. Or for example if it's possible to implement DMM reading while it's charging from a power bank.

In the review they mentions Winner Micro W806-C200 MCU, which is pretty limited, but there ale more chips on the PCB, but in general traces are not clearly visible.

So maybe, could somebody make hi-res photos of the internals? Sure just for educational purpose only!

Btw I've downloaded the firmware and the archive contains ch341ser driver/installer and 440kB firmware So it seems that any high speed communication with PC won't be possible.

I haven't bought this device yet, so I can't make the photos myself.

Thanks a lot!
 

[BillyO]

I would like to see what is connected where and gather as many information/datasheets as I can.

It is likely a 6 or more layer board.  How would you determine the connections through the internal layers?

What is the purpose of all this?

The com port is there for firmware updates only.  There is no file transfer or real-time image transfer capability.

[Fungus]

I wonder if they even are able to implement USB/OTG or any other high speed communication + other stuff. Or for example if it's possible to implement DMM reading while it's charging from a power bank.

DMM while connected to a charger would be a good hack for working on low voltage stuff on the bench all day.

But it's probably better done in firmware.

[BillyO]

DMM while connected to a charger would be a good hack for working on low voltage stuff on the bench all day.

But it's probably better done in firmware.

I think it's quite likely a hardware limitation.  While the MCU has a lot of serial options they come out on multi-purpose I/O pins that may be used for other things.  It may have only a single serial port exposed and shared between the DMM chip and the CH341.  If that's the case, I guess you could have it ask when you plug it into a USB power source if you want to do a firmware update or not.

[Fungus]

I think it's quite likely a hardware.  While the MCU has a lot of serial options they come out on multi-purpose I/O pins that may be used for other things.  It may have only a single serial port exposed and shared between the DMM chip and the CH341.  If that's the case I guess yo could have it ask when you plug it into a USB power source if you want to do a firmware update or not.

Sure, it migth be possible, but given the choice between uploading a firmware and opening it up to cut tracks on the PCB (or whatever) it think it would be much better to come up with a firmware fix.

[LucSVK]

I would like to see what is connected where and gather as many information/datasheets as I can.

It is likely a 6 or more layer board.  How would you determine the connections through the internal layers?

What is the purpose of all this?

The com port is there for firmware updates only.  There is no file transfer or real-time image transfer capability.

That's of course impossible from any photos. But you can find out more from hi-res detailed photos than from the YT review where you can see just a part of the board and not even clearly. From the review you can see that there are more chips ( some of them with removed names ). Maybe it could be possible to identify what they are (based on parts around), how they are connected together? Maybe it could open new possibilities .. For example in the review I can see two such chips outside the CAN. One could be AG32VF MCU/ASIC LQFP48 ( maybe AG32VF303CCT6 )? .. If it actually is, it has some interfaces too.. for example Ethernet PHY, USB2.0, SPI, UARTs .. How is this chip interconnected with the main MCU? Etc .. That's why at least the photos could be useful.

[taligentx]

Here are a few shots from when I was looking for a way to dump the W806 firmware:

[taligentx]

[taligentx]

[taligentx]

[taligentx]

Last of the photo set:

[taligentx]

While the MCU has a lot of serial options they come out on multi-purpose I/O pins that may be used for other things.  It may have only a single serial port exposed and shared between the DMM chip and the CH341.

This seems likely based on the "dmm uart init" message that is sometimes sent after flashing:

[LucSVK]

Taligentx: Thanks for the photos!

I can't see the ch341 on the photos. Where is it hidden? Under the beeper?

[billm]

If it's of any use, I've annotated a photo of the top of the circuit board.

[Atlan]

Is it emulated by software?  i.e. USB, which sounds like ch341 in the PC.  No physical chip is required.

[LucSVK]

If it's of any use, I've annotated a photo of the top of the circuit board.

Hi billm,

The chips named in you photo  as:
FPGA => It's very probably DMM chip
High Speed RAM =>  In newer revision it's AG32 MCU ( AG32VF303CCT6  ). It has 128 Kbytes of SRAM. On vendor's website they mentions (if I understand it correctly) that it's 2k CPLD too..
And there is a battery charging IC under the heatsink at the upper left corner .. - In newer revision it's IP2312

[Fungus]

They actually put in a special speech recognition chip? 

I thought it was just somebody at the company messing around one day.

[motoge]

Hello. Can you tell me where I can find the firmware v3.06?

[cte]

Hello. Can you tell me where I can find the firmware v3.06?

It hasn't been officially made available yet, but you can find v3.0.6_III on GitHub.

https://github.com/taligentx/FLSTweak/tree/main/Zeeweii_DSO3D12

[BillyO]

I can't see the ch341 on the photos. Where is it hidden? Under the beeper?

That may be the case.  That's where the USB connector is.

Yup - that's where it is.

[billm]

The chips named in you photo  as:
FPGA => It's very probably DMM chip

The W806-C200 has a 16 bit ADC which I had assumed would be used for the multimeter functions.

High Speed RAM =>  In newer revision it's AG32 MCU ( AG32VF303CCT6  ). It has 128 Kbytes of SRAM. On vendor's website they mentions (if I understand it correctly) that it's 2k CPLD too..

That is puzzling. The AG32VF303CCT6 has a maximum clock of 208 MHz which would normally make it far too slow to take samples from the high speed ADC at 250 MS/s. The data sheet says there is a 2k LE FPGA onboard, but I haven't found anything else much about it, apart from it having a total of 4 kB RAM (far too small to gather the ADC samples). Part of the FPGA seems to be dedicated to part of the internal clock tree.

There is some data on the AGRV2K FPGAs from the same company available. One of these appears to be similar to the one on the AG32 chip and there is some timing data given for these. Most times are in the range of 0.5 to 2 or so ns. I don't know whether these would add up in a way that would make a sequencer for transferring data to the 128 kB RAM at 250 MS/s, even if that RAM can be pushed to take the data at that rate.

[billm]

Here's an updated version of the annotated photo.