LPC55S6X USB0 in host mode

[manuela_mendez]

Hello NXP Experts,

I've few clarification questions on using USB0 as host on LPC55S6x:

1. UM11126, rev2.7, p832 table 780 says: "Enable USB0_VBUS pin for correct host operation. For example, it is required detect a change in the connection status." 
   1. what is the correct way to achieve this? can VBUS0_VBUS be tied permanently to 3.3v?
   2. what is the pullup recommendation to minimize the current draw? is there anything else required at the schematic level?
2. Could you explain USB0_VBUS role in host mode? LPC55x documentation has no coverage on this. Is there an older MCU doc that talks about this?
3. Does LPC55S6X-EVK support using USB0 as host? I see this being exposed as PIO22 on the headers, but not sure what else is needs to be done to get the host functional
4. Is there a SDK example that uses USB0 has host?

Thanks in advance!

[Alice_Yang · Accepted solution]

Hello @manuela_mendez 

• The USB0_VBUS should be connected to 5V.
• When USB0 functions as a host, the USB0_VBUS is used to supply power to the USB device and also to detect whether the device is connected or disconnected.
• The LPC55s6x-EVK supports USB0 as a host. Please refer to the LPCXpresso55s69 User Manual for configuring the hardware. Hardware please refer to schematic of lpcxpresso55s69-evk.

https://www.nxp.com/webapp/sps/download/preDownload.jsp?render=true 

https://www.nxp.com/webapp/Download?colCode=LPC55S69-SCH 

• The USB host example uses USB0 by default. Please refer to the relevant documentation for further details.

BR

Alice

[manuela_mendez]

Hello @Alice_Yang 

Thanks for the quick response.  I'll look into the resources you have provided.

Regd. you comment "The USB0_VBUS should be connected to 5V" --

on p44, Rev. 2.3 of LPC55S2X_LPC552X datasheet it states the following:

[6]
The corresponding VBUS must be connected to supply voltage when using the USB peripheral. USB0_VBUS is not 5 V tolerant pin and is tolerant up to
3.6 V only when the VDD is at operating level (minimum: 1.8 V). USB1_VBUS is 5 V tolerant pin regardless if the VDD supply is present or not.

it doesn't talk about the host mode, but still it is confusing - that was the reason for me to think it needs to be connected to 3v3.

[Alice_Yang]

Hello @manuela_mendez 

Yes, you are right. So design USB0_VBUS as below:

BR

Alice

[manuela_mendez]

Hello @Alice_Yang: thank you for the confirmation!