5 ms·

Oh, man. I'm surprised that card works at all with that wiring. High speed single ended signaling does not do well off-board. Have you done any kind of integrit

Oh, man. I'm surprised that card works at all with that wiring. High speed single ended signaling does not do well off-board. Have you done any kind of integrity testing, like writing a GB to the disk and then reading the checksum? If anyone is looking to do this mod, at least consider using a shielded ribbon cable like so: https://www.amazon.com/LANMU-Extension-Flexible-Monoprice-Raspberry/dp/B01D9JIUU0 https://www.amazon.com/LANMU-Extension-Flexible-Monoprice-Ra...

davisr 6y ago
Hi, I'm the author of this hack---the card works at 50 MHz with no errors.
reportingsjr 6y ago
SD cards typical aren't run on a very high speed bus. A couple of MHz is pretty typical and this sort of wiring is no problem at those speeds. Definitely no need for a shielded cable either.
- RL_Quine 6y ago
  Was going to say, I’ve run the stuff with whatever bits of cat5 cable I had on my desk, they’re not that fussy.
  - kevin_thibedeau 6y ago
    They're not that fussy at low speeds. You will have problems getting UHS cards to run at full speed.
q3k 6y ago
Data transfers in SD cards are CRC checked. In addition, the card will by default start in a 12.5MB/s mode at 3.3v, which is 25MHz per lane. That's not DC, but it's definitely slow enough to run on some pretty dodgy wiring. It will only switch to higher speed modes if requested, and if it actually works (falling back to lower speeds otherwise).
bronson 6y ago
That’s not shielded. I doubt it offers any more signal integrity than the 30awg wires nicely taped together. And the 30awg wires can go around corners without folding.
- jschwartzi 6y ago
  I have an FFC version of that product and it works very well. Whatever data rate reduction I might see from the additional length is overtaken in a really big way by my ability to use full-size SD cards instead of the micro-SD card slots my development boards usually come with. You definitely don't need a shielded cable. SD is very robust. Hell, I've seen people run SPI or I2C over similar lengths and types of cable and those two protocols are much less robust than SD.
castratikron 6y ago
I can't understand the negative sentiment in these replies. A ribbon cable is objectively a better design choice. If someone is attempting this mod themselves why would they not pick the best choice? We're all engineers, here, right? Do you all prefer to drive without wearing a seat belt as well?
- xodice 6y ago
  I think people were more put off by your amazement that it worked at all (and the "tone" which went with it), when there is no reason for it considering the original write-up has no issues with its implementation. Of course use what makes your project work the best, but don't go monster cable level on parts that need not.
- ciupicri 6y ago
  It's a better choice only if don't consider the cost or other factors. Engineering isn't about reaching a theoretical ideal "best", engineering is a about a practical compromise, getting things done.

davisr 6y ago

Hi, I'm the author of this hack---the card works at 50 MHz with no errors.

reportingsjr 6y ago

SD cards typical aren't run on a very high speed bus. A couple of MHz is pretty typical and this sort of wiring is no problem at those speeds. Definitely no need for a shielded cable either.

RL_Quine 6y ago
Was going to say, I’ve run the stuff with whatever bits of cat5 cable I had on my desk, they’re not that fussy.
- kevin_thibedeau 6y ago
  They're not that fussy at low speeds. You will have problems getting UHS cards to run at full speed.

q3k 6y ago

Data transfers in SD cards are CRC checked. In addition, the card will by default start in a 12.5MB/s mode at 3.3v, which is 25MHz per lane. That's not DC, but it's definitely slow enough to run on some pretty dodgy wiring. It will only switch to higher speed modes if requested, and if it actually works (falling back to lower speeds otherwise).

bronson 6y ago

That’s not shielded. I doubt it offers any more signal integrity than the 30awg wires nicely taped together. And the 30awg wires can go around corners without folding.

jschwartzi 6y ago
I have an FFC version of that product and it works very well. Whatever data rate reduction I might see from the additional length is overtaken in a really big way by my ability to use full-size SD cards instead of the micro-SD card slots my development boards usually come with. You definitely don't need a shielded cable. SD is very robust. Hell, I've seen people run SPI or I2C over similar lengths and types of cable and those two protocols are much less robust than SD.

castratikron 6y ago

I can't understand the negative sentiment in these replies. A ribbon cable is objectively a better design choice. If someone is attempting this mod themselves why would they not pick the best choice? We're all engineers, here, right? Do you all prefer to drive without wearing a seat belt as well?

xodice 6y ago
I think people were more put off by your amazement that it worked at all (and the "tone" which went with it), when there is no reason for it considering the original write-up has no issues with its implementation. Of course use what makes your project work the best, but don't go monster cable level on parts that need not.
ciupicri 6y ago
It's a better choice only if don't consider the cost or other factors. Engineering isn't about reaching a theoretical ideal "best", engineering is a about a practical compromise, getting things done.