LPC MicrocontrollersのトピックRe: USB on LPC54016JET100 with Vdd=1.8V

USB on LPC54016JET100 with Vdd=1.8V

andrewsglenn — Mon, 29 Jan 2024 19:32:08 GMT

We'd like to use the LPC54S016JET100 with Vdd=1.8V to interface with all our 1.8V peripherals.

Looking at the LPC540xx data sheet Table 12, minimum Vdd for USB Full Speed is 3.0V, but for High Speed is 1.71V, implying we should use USB1 for our interface.

My question is what happens if a Full-Speed device is connected to the High-Speed interface? Does it fail to enumerate as it needs a higher voltage?

What are the limitations of trying to use USB1 at 1.8V?

Re: USB on LPC54016JET100 with Vdd=1.8V

Alice_Yang — Wed, 31 Jan 2024 09:40:49 GMT

Hello @andrewsglenn

1> "My question is what happens if a Full-Speed device is connected to the High-Speed interface? Does it fail to enumerate as it needs a higher voltage? "

->> My understanding is that, for the working voltage of USB0( Full- speed) is 3.0 -3.6v.

The working voltage of usb1 is 1.71 - 3.6V.

2> "What are the limitations of trying to use USB1 at 1.8V?"

->> I.8v is the normal voltage limits.

Alice

Re: USB on LPC54016JET100 with Vdd=1.8V

andrewsglenn — Wed, 31 Jan 2024 15:18:11 GMT

So if you're using USB1 and it is connected in Full Speed mode rather than High Speed (due to limitations of the device connected) It will still work at Full Speed?

Re: USB on LPC54016JET100 with Vdd=1.8V

Alice_Yang — Fri, 02 Feb 2024 08:27:05 GMT

Hello @andrewsglenn

Yes, it will work as full speed.

And for Full Speed operation, VDD must be min of 3V.

Alice

Re: USB on LPC54016JET100 with Vdd=1.8V

andrewsglenn — Mon, 05 Feb 2024 16:13:21 GMT

Here's our setup:

VDD is 1.8V

USB1_AVDDC3V3 is 3.3V

USB1_AVDDTX3V3 is 3.3V

From what you are saying, USB1 will work as a High-Speed device, but will fail as a Full-Speed device because VDD is not 3V or higher?

Is this correct?

Re: USB on LPC54016JET100 with Vdd=1.8V

Alice_Yang — Thu, 08 Feb 2024 07:28:17 GMT

Hello @andrewsglenn

There is a little bit confusing and sorry about this, I will confirm with our internal.

Alice

Re: USB on LPC54016JET100 with Vdd=1.8V

Alice_Yang — Thu, 08 Feb 2024 07:42:27 GMT

Hello @andrewsglenn

If USB1 works as Full- speed device,

VDD is 1.8V

USB1_AVDDC3V3 is 3.3V

USB1_AVDDTX3V3 is 3.3V

Yes, USB1, will work.

Alice

Re: USB on LPC54016JET100 with Vdd=1.8V

andrewsglenn — Thu, 08 Feb 2024 15:06:49 GMT

Thank you.

Re: USB on LPC54016JET100 with Vdd=1.8V

andrewsglenn — Wed, 14 Feb 2024 17:56:08 GMT

Any luck finding a definitive answer?

Re: USB on LPC54016JET100 with Vdd=1.8V

Alice_Yang — Mon, 19 Feb 2024 01:37:07 GMT

Hello @andrewsglenn

Please see my reply last time:

Alice_Yang_0-1708306620170.png

Alice