Coupling 2 USB

Expert 2065 points

Other Parts Discussed in Thread: BQ24165

I noticed the TM4C has one USB available port.

I have a BQ24165 on our board which is as a power path switch : the device can be powered either by lipo battery or by 5V. The BQ24165 integrate the possibility to use also VBUS of USB plug to power the system.

In total it make two USB port on my board: one for the TM4C and one for the BQ24165, can I safely merge them together into a single one USB plug by mixing the VDBUS and the VBUS.

Below, my schematic related to those two USBs: .

over 9 years ago

0 Sai Reddy over 9 years ago

TI__Mastermind 22580 points

Hello Chrischina,

I have asked my colleague to comment on your question.

Thanks,
Sai

0 Amit Ashara over 9 years ago

TI__Guru**** 244400 points

Hello Chris,

Is the USB on TM4C12x device going to be used in Device or Host or OTG mode?

Regards
Amit

0 C over 9 years ago in reply to Amit Ashara

Expert 2065 points

Hello Amit,
The USb on TM4C12X could be use mostly to power the current device (not to power another device) and transfer data from a TF CARD or EEPROIM inside the device to a computer for example. It will not be used to power any device in the other direction.

0 Amit Ashara over 9 years ago in reply to C

TI__Guru**** 244400 points

Hello Chris.

So it would be a Device only mode. And under no condition will it be expected to be in Host Mode.

If that is the case, then only route the DP-DM to the TM4C12x device and use the VBUS for the BQ device.

Regards
Amit

0 C over 9 years ago in reply to Amit Ashara

Expert 2065 points

It means you confirm I can connect both on the same port, right ?

0 Amit Ashara over 9 years ago in reply to C

TI__Guru**** 244400 points

Hello Chris

What I am telling is if the BQxx device does not need USB DP/DM lines and TM4C12x is only going to be in device mode (then it does not need USBVBUS and ID).

Regards
Amit

0 C over 9 years ago in reply to Amit Ashara

Expert 2065 points

I am confused. My question is this :
Can I link the two usb VBUS 5V DC together and make only one USb plug who can both power the BQ and recharge the battery for example while keep being able to use data with TM4C to pick up some data on memory ?

0 Amit Ashara over 9 years ago in reply to C

TI__Guru**** 244400 points

Hello Chris,

Technically you need only one connector. The VBUS and GND go to BQ device and DP-DM goes to the TM4C12x device.

Personally, I have not tried the same.

Regards
Amit

0 C over 9 years ago in reply to Amit Ashara

Expert 2065 points

ok, this is what I was thinking. I thought I could do this, I am just concerned by those 3 capacitors plugged on vbus of the TM4C123G but not present on the BQ... Any comments about this ?

0 Amit Ashara over 9 years ago in reply to C

TI__Guru**** 244400 points

Hello Chris,

I am not sure either what those 3 capacitors are for?

Regards
Amit

0 C over 9 years ago in reply to Amit Ashara

Expert 2065 points

I don't know either but they were in reference design of DK...which is made by TI...

0 Amit Ashara over 9 years ago in reply to C

TI__Guru**** 244400 points

Hello Chris

Please note that LaunchPads and EVM's are for evaluation. They are not supposed to be production reference designs so addition of cap's like that would have been done (and omissions as well). You must refer to the System Design Guidelines for TM4C123x for proper design guidelines.

Regards
Amit

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Coupling 2 USB