LCP55S16 USB0 and USB1 difference in hardware design

[JaehoonLee13]

Hello,

We are designing a biomedical device which collects bio-data and streams out through USB using LCP55S16. There are two USB ports -USB0 for FS and USB1 for HS.

I understand that USB1 HS supports FS protocol. Presumably we are using only a full speed USB 2.0 then I guess either USB0 or USB1 work. However, I want to understand the difference between using USB0 and USB1 in hardware design perspective. 

After going through the datasheet, my understanding is USB0 can be operated crystal-less (no external 16MHz crystal needed) ,while USB1 requires the external crystal through xtal32N/xtal32P pins. Is this the only difference between USB0 and USB1? If so, I assume LCP55s16 MCU integrates two separate PHY for USB0 and USB1 (correct me if I am wrong). 

In summary, my questions are as follows:

1) Do only USB1 require an external crystal, while USB0 can operate crystal-lessly?

2) LCP55S16 has two separate USB PHY for USB0/USB1?

3) Is there any other difference between USB0 and USB1?

Thanks!

Jaehoon

[Alice_Yang]

Hello @JaehoonLee13 

1) Do only USB1 require an external crystal, while USB0 can operate crystal-lessly?

->> USB0 full-speed device supporting crystal-less operation in device mode using the software library example in technical note https://www.nxp.com.cn/docs/en/application-note/TN00065.pdf .

2) LCP55S16 has two separate USB PHY for USB0/USB1?

->> Yes.

3) Is there any other difference between USB0 and USB1?

->>Almost no other difference.

BR

Alice

[JaehoonLee13]

Thanks, Alice for your response.

Given that there is no difference between USB0 and USB1 and USB1 can support FS, why the MCU has two separate USB PHYs? 

If the USB1 operates only in FS mode, can it be operated crystal-less as well? 

[Alice_Yang]

Hello @JaehoonLee13 

"If the USB1 operates only in FS mode, can it be operated crystal-less as well? "

->> No, no matter HS mode or FS mode, USB1 must use external crystal.

BR

Alice