Posts: 1
Joined: Tue Nov 19, 2019 12:03 pm

USB Questions

Tue Nov 19, 2019 12:14 pm

Hi all,

I will be making a PCB for the Raspberry Pi CM3+ and I have some questions regarding the USB port.
I will only need the Pi to be a master in my application as I will have pre-programmed the flash memory using the CM dev kit which allows you to connect the module to a PC for programming the flash.

I would like to have just a single USB host port on the PCB. Is it simply a matter of connecting the USB pins to 165 and 167 on the 200 pin SODIMM connector? Do I need any protection between the Pi and the connector? Should I supply a constant 5V to the USB or is it better to be able to cycle this supply from a GPIO through a transistor?

Also on the CM3 dev kit there is an IC U5 on the USB lines, does anybody know what that is for? The CM3 dev kit seems to have 2 USB ports one for USB slave and one for HOST, is that what this IC is doing?


Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Re: USB Questions

Tue Nov 19, 2019 3:06 pm

The full schematics for the CMIO are available at https://www.raspberrypi.org/documentati ... IO_3p0.zip. From those the function of U5 is obvious.
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