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Release Notes for StellarisWare Revision 5727 (March 2, 2010)

behave the same way as the original macros regardless of whether they are passed signed or

unsigned values. These macros were replaced in the previous release to work around an IAR 5.41

compiler bug. The edit will be removed once a toolchain ﬁx is available.

14.6 New Features in Stellaris USB Librar y

14.6.1 Added the ability to use the USB VBUS ﬁlter (Reference 11339)

Some Stellaris microcontrollers with USB OTG functionality have the ability to ignore short dips

in VBUS. These momentary dips are usually caused by inrush current to a device and can drop

VBUS below VBUS valid. When VBUS drops below VBUS valid level the USB OTG controller

will exit host mode and drop VBUS to below session valid level and attempt to power the de-

vice again. The VBUS ﬁlter is enabled by calling the USBHostPwrConﬁg() function with the

USB_HOST_PWREN_FILTER bit set.

14.6.2 Added Isochronous Host controller support to USB Library (Refer-

ence 11528)

The USB library did not have support for using the Host controller with Isochronous devices. This

update adds support for USB Isochronous Audio devices and provides an example of how to enu-

merate other USB Isochronous devices and interact with Isochronous IN and OUT endpoints. See

the USB library documentation for more information on using the USB Host Isochronous audio

class.

14.6.3 Added new function to allocate FIFO to an endpoint (Reference

11557)

The USBHCDPipeAlloc() was the only method used to allocate USB FIFO memory to endpoints

and used a ﬁxed allocation of 64 bytes per endpoint. To work with endpoints that have larger FIFO

requirements, like Isochronous endpoints, a new USBHCDPipeAllocSize() function was added that

adds a size parameter to attempt to allocate memory to an endpoint. This allows Isochronous

endpoints to allocate up to 1024 bytes to a single endpoint while still allowing Bulk, Interrupt and

Control endpoints to use the standard 64 byte FIFOs.

14.7 Bug Fixes in Stellaris USB Library

14.7.1 USBlib overwrites power conﬁguration in OTG mode (Reference

11338)

When using OTG mode, usblib was using a ﬁxed setting for the power control pins and ignoring

the application supplied settings. OTG mode now correctly uses the settings that the application

provides to usblib.

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