LPC11 USB Low-Speed without Crystal

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LPC11 USB Low-Speed without Crystal

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lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by tenxp on Sat May 11 12:20:03 MST 2013

We are intending to use the LPC11 as a Low-Speed USB device mainly to save the cost of using a crystal.


It appears from the User manual that the internal RC can be used for this purpose.


Just wondering ...


- Has anyone done so successfully


- Is there a way to get the internal MSC bootloader to startup in Low-speed ?


- Is source code available for the MSC bootloader and can the one in the MCU be replaced ?


Thanks,


Daraius

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lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by NXP_Paul on Tue May 21 06:30:06 MST 2013

Daraius
Unfortunately, the information you received was not correct.  The LPC11Uxx microcontrollers do not support low-speed USB.  I have confirmed this with the person who designed the USB peripheral.
The conflicting information in the user's manual and data sheet will be removed.  Thank you for bringing this to our attention.
-paul

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lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by tenxp on Mon May 13 14:13:19 MST 2013

Hi Paul:


Pg 26, table 18 in the User manual at...


<a style="color: #598fde; font-size: 13px; outline: none; font-family: arial; line-height: normal; background-color: #ffffff;" href="http://www.nxp.com/documents/user_manual/UM10462.pdf" target="_blank">http://www.nxp.com/documents/user_manual/UM10462.pdf</a>


states that the IRC is suitable for Low-Speed USB operation....


Similarly in Sect 11.4.7


And a search for "low-speed" in the manual finds other mentions of Low-Speed USB.


I also had this confirmed with the factory via Future Electronics.


So my question then becomes - I need a Low-Speed (no crystal) USB bootloader for the lowest cost solution.


Thanks and Regards


Daraius

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lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by NXP_Paul on Mon May 13 13:38:27 MST 2013

Daraius
The LPC11U family only supports full-speed USB.  Note that the features section of the data sheet specifies:
* USB 2.0 full-speed device controller
-paul

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