Products > Test Equipment
Picoscope Hack
_Wim_:
--- Quote from: markone on December 04, 2022, 06:53:51 pm ---Which table were you referring to ?
--- End quote ---
The list with models attached as a txt-file in the first post
markone:
--- Quote from: _Wim_ on December 04, 2022, 06:59:07 pm ---
--- Quote from: markone on December 04, 2022, 06:53:51 pm ---Which table were you referring to ?
--- End quote ---
The list with models attached as a txt-file in the first post
--- End quote ---
Damn, age is taking the toll, I have to confess that I spent some time looking for it :palm:
Ok, now it's all crystal clear :
PS5442B = 94
PS5443A = 95
PS5443B = 96
PS5444A = 97
PS5444B = 98
I finally understood where the offset value of 4 come from :D
I wonder if the method you used to fix the checksum computation will work in every occasion, I have read the related algorithm description on Sigrok site and if I well understood the way it works it could be not the case.
Have you applied the subtraction several times at different address or it worked at first try ?
_Wim_:
--- Quote from: markone on December 04, 2022, 07:47:35 pm ---I wonder if the method you used to fix the checksum computation will work in every occasion, I have read the related algorithm description on Sigrok site and if I well understood the way it works it could be not the case.
Have you applied the subtraction several times at different address or it worked at first try ?
--- End quote ---
Yes, it might not work in some case where the byte sum already overflows in the bytes surrounding the model number. In my case it did however work at first try (I immediately saw a different scope type when I connected via USB), but I had to experiment a bit to find the correct model number.
Edit: see post below, should probably always work if my reasoning is correct
_Wim_:
--- Quote from: _Wim_ on December 04, 2022, 08:02:05 pm ---Yes, it might not work in some case where the byte sum already overflows in the bytes surrounding the model number.
--- End quote ---
Forgot to mention, I calculated the 14-bit sum for the signed bytes in Excel, and for the entire 256 bytes, I did not have any overflow occurring. The first overflow occurred only at byte "780".
As we are only playing around with the 32 first bytes than can contain a number between -127 & 128, is it not possible to overflow a 14-bit number as the sum can be max 4096, so I do think this trick should always work.
voltsandjolts:
--- Quote from: markone on December 04, 2022, 06:53:51 pm ---Thank you very much, what you report confirms that they used the standard FX2 address for E2PROM in generic device mode, and this is a good news ;)
--- End quote ---
Ahha, then fx2tool is your new friend >:D
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