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Hantek HDG2002B AWG: 5Mhz or 100MHz? Let's see!
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idpromnut:
It would be an interesting project; I have very little experience with reverse engineering these types of devices, but I do have a *bit* of linux experience. I might be able to help out. I'm guessing they are using a custom graphical UI and not some variant of X.
idpromnut:
Of course I say this and what's the first thing I say to myself? "Hmm, I wonder where I would start if I were to try and figure out how to re-write this thing..."

I fired up the console and the first thing I noted is that I think the base Linux distro is actually a variant of Google's Android OS.  Interesting. :)  We might should create a new thread for this?
alex.forencich:

--- Quote from: idpromnut on October 26, 2014, 12:35:17 am ---Of course I say this and what's the first thing I say to myself? "Hmm, I wonder where I would start if I were to try and figure out how to re-write this thing..."

I fired up the console and the first thing I noted is that I think the base Linux distro is actually a variant of Google's Android OS.  Interesting. :)  We might should create a new thread for this?

--- End quote ---

Well, that probably explains the shitty performance.  This is the chip: http://www.samsung.com/global/business/semiconductor/product/application/detail?iaId=836&productId=7116 .  Looks like a relatively standard ARM 9 based SoC.  I wonder if we could get a reference design from Samsung that at least covers the software. 

If we do reimplement this, we either do it right or we don't do it at all.  Basically, I'm thinking I can figure out the FPGA and the front end and write a new FPGA configuration so long as there is somebody else to figure out the OS on the ARM chip.  I have some tools to reverse engineer FPGA interconnections, though I may need a board that I can yank some of the BGAs off of (namely the memory chips). 
idpromnut:
Yup, that's the same conclusion I came to from /proc/cpuinfo and a bit of digging. There seems to be perhaps an Android build for this SoC. I am looking into that now, and to see if it will be easy to rebuild an Android  firmware image that I could try and get working on my unit. Got to back up my firmware again before trying that though.
alex.forencich:

--- Quote from: idpromnut on October 26, 2014, 01:05:16 am ---Yup, that's the same conclusion I came to from /proc/cpuinfo and a bit of digging. There seems to be perhaps an Android build for this SoC. I am looking into that now, and to see if it will be easy to rebuild an Android  firmware image that I could try and get working on my unit. Got to back up my firmware again before trying that though.

--- End quote ---

Sounds like a plan.  I am taking a look at the front end and FPGA connections.  Looks like the connection between the FPGA and the ARM chip is only 8 wires, likely 4 one way and 4 the other way so they can use digital isolators.  I presume it connects to one of the SPI ports on the ARM chip.  On the FPGA side it most likely connects to the config pins, which would be recycled for communications.  The FPGA is a Xilinx Spartan 6 LX16 CSG 324.  Not sure about the speed grade. 

Also, there is what appears to be a 9-bit R2R DAC with two-stage LC filter connected to the FPGA.  No idea what this is intended for, though. 

The front-end relays are controlled by two 74HC595 shift registers, connected in series.  That still leaves 4 outputs on each '595 unaccounted for, though. 
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