topic Re: LPC4370 - Speed with VCOM in LPC Microcontrollers

LPC4370 - Speed with VCOM

mattiad — Wed, 29 Aug 2018 10:12:14 GMT

Dears,

I'm using USB0 port of my LPC4370 as a virtual com.

In this case, which is the speed of the USB communication?

Full speed or High speed?

Best Regards,

Mattia

Re: LPC4370 - Speed with VCOM

soledad — Wed, 29 Aug 2018 14:12:13 GMT

Hi,

USB0 supports all high-speed, full-speed, and low-speed USB-compliant peripherals.

If you are using the usbd_rom_cdc_vcom LPCOpen example, then is high speed.

Have a great day,
Sol

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Re: LPC4370 - Speed with VCOM

mattiad — Thu, 30 Aug 2018 07:07:24 GMT

Thank you Soledad!

I don't understand another thing: in some evaluation boards there are 33Ohm resistances in D+ and D- lines.

In this schematic

https://www.nxp.com/downloads/en/design-support/LPC4330_Xplorer_schematic_OM13027.pdf

33Ohm are in the USB1 port and not in USB0 port.

Why in some cases are added and in another cases not?

I suppose that fore a Virtual COM link it's better if they are added.

Best Regards,

Mattia