Quote
_dev-null - 2021-06-02 1:37 AM
Hi!
PS: The picture attached is marketing at its finest - they marked the inductors as capacitors and vice versa ... if you are really interested google for USB host controller design and have a look at sample schematics.
Regards
Stefan
Well said my friend... yet, quite good for a laugh!!
I had to give my brain a rest after my initial attempt at wiring things up, but wow, now the schematic and components all make sense. Your component list is great! I see the EMI filters, and need "3 "100uf capacitors according to schematic. Thanks for that!!!
In fact, I have an idea worth considering/trying that may really simplify things:
Eliminate the need for the power sense and power control wires, and the MAX1607 switch and instead use a
(cheap
) external 5 volt power source/inverter board with common ground to capacitor on motherboard
(that could be powered by the J720 12 volt charge port or docking port 12v with a manual switch perhaps
).
If this works, wiring could be easy, requiring only 2 data lines and ground wire
(to the capacitor
). Still need to change out the 10k SMD resistor though and remove pcmcia cover, etc.
![](https://www.hpcfactor.com/forums/images/emoticons/icon_smile_sad.gif)
How important is that resistor change, critical??? Anyway, worth exploring! At least until parts arrive...
Since USB Transient suppression is optional
( requires the SN75240 chip and 15k ohm resistors
) at this prototyping stage, only the 24 ohm resistors are needed and a 5volt power supply/inverter/or "wall wart
( by tapping into a USB "extension port" cable for ground and +D -D
)" I will give it a try, wish me luck!
Cheers!
joval
Edited by joval 2021-06-02 6:11 PM