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SainSmart DDS120 & DDS140 USB Oscilloscope

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doctormord:
I once had a friend like you, who teached me "model tiny" ASM this way. :))

So my first "program" was reboot.com " 0xCD 0x19"

Regards, doc

doctormord:

--- Quote from: psynapse on October 13, 2014, 02:41:36 pm ---


Ganz. I think that the RAM functions as a poor mans FIFO,  it is filled under the control of the CPLD and then dumped into the regular FIFO, leading to regular periods when the scope is blind.  I (well we DDS140 owners) can hope that the CPLD runs in two modes, either (at lower speeds) passing AD data straight to the true FIFO as per the DDS120 and just for higher speeds it directs the AD to the SRAM and then dumps the SRAM to the FIFO

--- End quote ---

To my understanding, running the scope this way on "high speed" would only work for triggered signals (so just getting enough samples to refresh the screen) not in free running mode, or will, until the buffer gets full.

psynapse:
Doctormord,

I agree with you, and that is exactly the problem ... there is no hardware trigger (confirmed by sainsmart), the software just guesses  :(

On a brighter note, the code inspection is progressing.  I believe that the "magic bullets" of donut6 are:

db(022h)
db(023h)
db(024h)
db(033h)
db(034h)
db(035h)
db(050h)
db(060h)
db(061h)
db(062h)
db(063h)
db(070h)
db(071h)
db(072h)
db(073h)
db(074h)
db(075h)
db(076h)
db(077h)
db(078h)
db(079h)
db(07Ah)
db(07Bh)
db(07Ch)
db(07Dh)
db(090h)
db(094h)
db(0D0h)
db(0D1h)

I think these are all the command codes (first byte) to the DDS140 scope.  The commands appear in the second byte of the 8 byte setup data (please see attached diagram of USB packet structure)

Tomorrow, I will start exploring what parameters they import, but I have noted that many of them do bit set/clr to the I/O ports. Also, what is the first byte?

Some examples 33 and 34 manipulate port C.3 and E.2 in complementary manner
76 through 7d have similar behaviours to each other and take one byte parameter (which sets key parameters in the direct RAM space below 80h) etc



doctormord:
As far as I remember, the DDS140 should have an external trigger input. (seen in the software trigger menu, CH1/CH2/EXT)

psynapse:
It has ext marked, but no external connection.  It make me ask:-does one exist "inside" the dds140, or is this in some way generic software?

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