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juancgarcia / HID-Relay

Arduino project to convert wired USB HID device to Bluetooth (pipes USB HID reports out through a Bluetooth HID module)
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Could this be made to work with an Arduino Pro Micro? #2

Closed prashcr closed 6 years ago

prashcr commented 7 years ago

I'm new to electronics and I have a bunch of spare pro micros so I was wondering if I could use those instead.

juancgarcia commented 7 years ago

It's seems not all of the pin assignments line up between the pro mini and pro micro

SS, MOSI, MISO, SCK are 10,11,12,13 on the mini and 10,16,14,15 on the micro. I think it may be possible to remap these pins in your sketch, but you'll need to look into the usb host controller documentation to know for sure.

Of more concern is one pin where the host controller expects reset, the micro provides gnd. If connected without modification, I believe this would cause the host controller to constantly boot loop. This will require physically cutting a trace on the host shield and adding a jumper wire to the proper reset pin.

usb host shield

pro micro

pro mini

prashcr commented 7 years ago

Thank you so much for the detailed explanation.

With some further research, it seems an alternative to connecting the pro micro's reset to the host shield's reset would be to connect the pro micro's vcc to the host shield's reset instead.

Example with Pro Micro: https://geekhack.org/index.php?topic=80421.0
Example with Teensy: https://www.pjrc.com/teensy/td_libs_USBHostShield.html

juancgarcia commented 7 years ago

That looks like it might work then.