My issue, that using the above mentioned / attached USBPorts.kext, all ports are max 500 mA, even the USB 3.0 ports.
From my understanding, with this kext, I don't need any more kexts such as "USBInjectAll.kext" or other fixes, right?
Hi
@hackmymac,
@jiffyslot,
@e-troc and others enquiring about USB and power to charge phones and also the Apple Superdrive.
Firstly
@hackmymac the answer is yes, you don't need anymore kexts, just follow my post(s) to
@jiffyslot and you should be good to go.
Ok, here is what I've found out. If you look
at this article on the Apple site, it's apparent that some genuine Mac models have the capability of providing more power than the USB specs.
Our iMac is not a genuine Mac in the USB department and cannot provide the sort of current (amperage), that an Apple iMac can.
I connected my USB DVD burner (I don't have a Superdrive), and with a standard USB cable, it will not connect under this Hack or when I boot into Windows. It just keeps on seeking and reseting (clunk, clunk!) because the 5V line is dropping down (voltage sag), If I connect it via the special cable, which has two USB male A ports to the one USB Mini port, then because the USB ports can supply up to 500ma from each port all is well and my Hack works fine.
I suspect that the USB cable on the back of the Apple SuperDrive is hardwired in, i.e. it does not have a USB plug? If this is the case, then you have two options:
- Buy a cable like this that has a Female USB A port to 2 x USB A Male ports: Amazon has a couple.
- Use a powered Hub that can supply the required power.
Personally, I'd go for the 'Y' cable approach, option 1.
Also there is an option in Clover Configurator that you can try for USB "HighCurrent". I could not see any difference when I connected my iPhone and measured the voltage and current using my in-line USB power meter. The option is like this:
Also this motherboard allows you to step up the 5V in 0.1V increments to a max of 5.3V (in the BIOS) on the two USB ports F_USB30 (USB 3.1 Gen 1 Header) that in my case go to the front two USB ports. For some this might be enough for slightly higher power devices to connect and allow for the voltage drop across the USB cable.
USB cables are also not created equal, some have very 'puny' 5V & Ground (0V) cables that drop a significant amount of voltage when the device draws a high amount of current e.g a DVD drive when it's motor spins up it draws in excess of 1A. So say for example it draws a 1.8A 'spike' of current and the Usb cable combined 0V & 5V wires resistance measures 0.4 Ohms.
So the voltage drop will be 1.8 x 0.4 = 0.72 Volts therefore the device then only sees 5V - 0.72V = 4.28V
The
USB Voltage specs for USB2 is 5V +/- 0.25V -0.6V and for USB3 is 5V +/- 0.25V -0.55V
So in this example using a USB2 device, the voltage sag is out of spec from the minimum 4.4V. This in my external USB DVD player is why it sits there continually turning on and off the motor as the current draw causes the voltage to jump up and down and the onboard controller resets because it falls below the voltage required for it's logic chips and micro controller and then cycle happens all over again... 'rinse & repeat'!.
I might add to this post an oscilloscope picture of this if I get time .
In summary, our iMac's are close to an Apple iMac, but there are differences, some we just have to work around.
Jim
