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Hantek DSO2xxx schematics

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pu6k1n:
I copied the circuit completely from the DSO2C10 power supply unit, do not judge strictly  :)

morgan_flint:
Hello, pcprogrammer!

I think I found an error in the schematics (Mainboard/External_Interfaces): R21 should be R16 and R16 should be R196.

I'm thinking of installing J4 for the serial port (or, maybe, a more practical connector), so I was inspecting this part of the board. BTW, I've been using the serial port extensively and SERIAL_READY signal seems to be unnecessary for it to work. What could be its purpose?

I've also noted that if the serial to USB is connected to the scope but not to the PC the boot procedure stops when showing the QR code and freezes there (maybe that's the purpose...).

Thanks for your (immense) work!

pcprogrammer:
Hi morgan_flint, looks like you are onto something :)

Looking at the photo I used to do this work also shows that the connector is J2 instead of J4.

R21 needs to be named R16 indeed. Also noticed that R32 has a ohms value assigned, but since it is not on the board it will not be correct.

I will look into this further and modify the schematics.

The signal SERIAL_READY is connected to the F1C100s and I just named it as such because I think it is some handshake signal, but most likely not used in the software. The fact that the scope hangs when a USB to serial interface is connected, probably has to do with the boot loader. I have seen this happen on a Lichee nano too, when I was playing around with linux on a F1C100s. Not sure why this happens. Was in the time I was starting with the reverse engineering of the FNIRSI-1013D. Did not investigate it further since the FNIRSI scope does not use linux.

But good to know this, because I was thinking of integrating a CH340 USB to serial module in the scope, but if it would need to be connected to a PC to allow the scope to start is not what one wants :palm:

pcprogrammer:
The schematic has been updated and uploaded to the repository.

https://github.com/pecostm32/Hantek_DSO2000/tree/main/Schematics

DavidAlfa:
I'm convinced that what you call "serial ready" signal was actually used as some sort of system reset when the system hanged during development. Probably a hardware interrupt was set on pin value change.
The issue you're having is probably caused by the Rx line being pulled low by the unconnected (Thus unpowered) usb-ttl adaptor, causing random chars being received by the bootloader, entering the boot shell.

Also check there's a tiny via just over R32, in the trace going to the CPU.
It must be going somewhere else, your schematic seems to be lacking this.
I checked that back in the day, but can't remember, perhabs it also goes to the fpga reset pin (RECONFIG)?

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