topic LPC4357 USB0 as device, are reference pins needed? in LPC Microcontrollers

LPC4357 USB0 as device, are reference pins needed?

__placeholder__ — Tue, 08 Aug 2017 22:51:11 GMT

I am using the LPC4357 USB0 strictly as an USB device. Do I need to connect the USB0_VSSA_TERM, USB0_VSSA_REF, USB0_VDDA3V3, USB0_VDDA3V3_DRIVER and USB0_RREF pins, or are they only used when the UDB is configured as a host or OTG? Or is this part of the built in USB interface electrical test software?

All the reference designs tend to include everything possible, so they have the host and OTG configuration.

The manual is vague about USB0_VDDA3V3 & USB0_VDDA3V3_DRIVER if they are the supply for the whole USB module, or just the host part. A block diagram would help.

Re: LPC4357 USB0 as device, are reference pins needed?

jeremyzhou — Thu, 10 Aug 2017 02:40:05 GMT

Hi,

Thank you for your interest in NXP Semiconductor products and

for the opportunity to serve you.

I've attached the sch of MCB4300, you can refer to the USB portion in this sch.

http://www.keil.com/mcb4300/mcb4300v1-3-schematics.pdf

Have a great day,

TIC

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

Re: LPC4357 USB0 as device, are reference pins needed?

__placeholder__ — Fri, 11 Aug 2017 04:10:15 GMT

Yes, but that does not answer my question.

Are pins USB0_VSSA_TERM, USB0_VSSA_REF, USB0_VDDA3V3, USB0_VDDA3V3_DRIVER and USB0_RREF used for both device & host mode, or just host/OTG?

I can connect everything up as per the schematic, and I'm sure it will work, but why place unnecessary components?.

Re: LPC4357 USB0 as device, are reference pins needed?

jeremyzhou — Fri, 11 Aug 2017 07:39:49 GMT

Hi __PLACEHOLDER__ __PLACEHOLDER__,

1) Are pins USB0_VSSA_TERM, USB0_VSSA_REF, USB0_VDDA3V3, USB0_VDDA3V3_DRIVER and USB0_RREF used for both device & host mode, or just host/OTG?

These pins connection are same in different modes, the portion circuit is needed for device mode, you can connect the 5V to VBUS pin of USB0 directly, then the LM3526M is able to be removed too.

Have a great day,

TIC