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LM3S3748 USB host is not working with new lot of controllers, but works fine with older lot.
I am using LM3S3748 controller for application which requires reading a USB mass storage device, i even tried with your example codes and it works fine in older lot of controllers and the same example code is not working in newer lot controllers. lot numbers are mentioned bellow.
I have gone through the Errata published for the same chip and implemented workaround for USB HOST. i.e PB1 +5V and PB0 GND.
Please help me on this.
New lot controllers not working (LM3S3748 > IQC50A0SD > $9-21P092H)
Where as it works fine with old lot (LM3S3748 >IQC50A0SD >$9-03P087H)
Thanks and Regards,
Manohar Y G.
Manohar Y G same example code is not working in newer
Now infamous, "not working," plagues would-be helpers once again! Of course you know exactly what you mean - those reading have no clue! You state that you've "gone thru" errata - again without clarifying "which errata." Errata released as recently as 02 April 2012 (Rev 2.8) starts by noting, "USB PLL may fail to lock after reset." As we're told nothing by "not working" - can only guess if this is significant.
May prove helpful (for current poster and recent others) to place yourself "bit more" in the position of remote helper - who is without your full knowledge of your development. We need pertinent detail - beginning with basic failure description: (i.e. what, where, when, why, how - coupled with your investigations & findings...)
Is your system clock frequency set to 20 MHz? If so, this problem may be related to the Oct. 2011 changes in this class of device that enable USB hub functionality. In order to ensure compatibility with USB hubs in all devices produced after Oct. 2011, we had to increase the minimum system clock frequency for USB to 30 MHz. If you attempt to use USB while the system clock is at 20 MHz, it may no longer function correctly. This should be documented in the latest version of the errata for this device.
Forgive me - but in the effort to be "correct" hallowed "not working" is tacitly blessed - thus encouraged - and will live on and on and on...
Dear ChristianAs per the Errata published on Apr 2012 rev 2.9 "USB Host controller may not be used to communicate with a low-speed Device when connected through a hub". But i am configuring LM3S3748 in permanent HOST mode to communicate with external mass storage device (Pen drive).Do i need to operate my system on 30MHz in order to use it in HOST mode?Could you please help me on same.RegardsManohar Y G
Yes, regardless of host, device, or OTG mode, the new minimum frequency for USB operation on the LM3S3748 is 30 MHz. This applies even if you are not using a hub.
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