Matrix user forums

Hi all,

Back in 2011 with some help from Ben here I completed a USB keyboard design on a PIC18f13K50 which was programmed using Flowcode and that's fine.

When I use it on my old Mac or Windows 7 PC it runs perfectly but on the latest post 2012 Intel MacBook Pro it doesn't recognise the device at all.

Some investigation on the Apple site showed:

snip>>

Learn more about the power available via USB on Apple computers and displays and how to use peripheral devices that may require more power than is available through the USB port.

Apple computers and displays with USB 1.1 or USB 2 ports provide:
Up to 500 mA (Milliamps) at 5 V (Volts) to most Apple USB peripherals and all USB peripherals not made by Apple in compliance with USB specifications.

Apple computers with USB 3 ports provide:
Up to 900 mA (milliamps) at 5 V (Volts) to most Apple USB peripherals and all USB peripherals not made by Apple in compliance with USB specifications.

Note: Some USB peripheral devices not manufactured by Apple may have unique power requirements. These may exceed the power allotment on an individual USB port. Those devices may require you connect them to multiple USB ports or may have external power sources that must be present for them to function.

snip>>

My device doesn't show up on a USB 3 port so the question is what exactly is the "USB compliance" Apple is on about? I checked on the Microchip web site and they said their chips were compliant so is there something I'm doing wrong please does anybody know.

tia

James :-}

Hi James,

The Power usage is specified from the USB component properties however it should be in the correct USB range for it to work.

I haven't touched a MAC in years but could it be that you need updated drivers to correctly drive the USB3 hardware ports?

MACs are normally quite good at things like this but I can't see the embedded device being to blame as it works with everything else.

It's driving me nuts Ben. Here's the report from Xcode (the Mac's development software) and it shows the battleship Mac keyboard (huge thing - 20 function keys) only takes 20mA so 50mA should be enough for the PIC.

I'm going to reprogram the devices and see if it works then because the ECIO comes up as a Keyboard OK but not my board!

Thanks anyway...