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.
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