NuttX-6.16
----------

The 83rd release of NuttX, Version 6.16, was made on March 10, 2012,
and is available for download from the SourceForge website. Note
that release consists of two tarballs: nuttx-6.16.tar.gz and
apps-6.16.tar.gz. Both may be needed (see the top-level nuttx/README.txt
file for build information).

This release corresponds with SVN release number: r4475

New features and extended functionality:

* ARMv7M Support: Includes new, streamlined Cortex-M exception
handling provided by Mike Smith. Context switching support for the
Cortex-M4 FPU registers is now provided (in both "lazy" and "non-lazy"
modes)

* General Drivers: Added a generic "upper half" Quadrature Encoder driver.
The USB CDC/ACM serial driver can now be dynamically connected or
disconnected from the host (programmatically or using NSH commands).

* STM32 Drivers: Added a "lower half" Quadrature Encoder driver.
Verified the STM32 F4 DMA driver; Added F4 DMA support to the existing
STM32 SDIO driver.

* STM32 Board Support. Added support for the STM32 F2 family and
for the STM3220G-EVAL board (contributed by Gary Teravskis).
Support is now included for C++ static constructors (verified using
the Atollic toolchain). Added support for the SRAM available on the
STM3240G-EVAL board.

* PIC32 Drivers. PIC32MX USB (device) driver is now functional.
The PIC32MX Ethernet driver not yet fully verified (and an
unverified SPI driver is also available).

* Networking. Added a lower-level, thread-independent socket layer.
Parts of this layer were created in 6.15 to support the FTPD
controlling terminal; this support has been extended in order
to support an NFS file system (not yet released).

* NuttShell (NSH). NSH will now support a USB serial connection for
the console (such as CDC/ACM). This is useful in environments
where there is no physical serial port on the board.

* Build System. Reorgnaization of networking header files.

Critical Bugfixes. The following bug fixes are considered critical:

* Networking: Fixed a "leak" in the TCP/IP read-ahead buffering logic.
Corrected an error in TCP/IP sequence numbering/ACK logic which
occurred when read-ahead buffering memory is exhausted.

* STM32 Drivers: Fixed an buffer sizing error in the STM32 Ethernet
driver.

Additional Bugfixes: Other important bug fixes are listed below. See
the ChangeLog of a complete, detailed list of bug fixes.

* Networking: Corrected recv()/recvfrom() return value. Added logic to
monitor for loss of connection after a new connection has been
established via accept() (Contributed by Max Nekludov). Add
logic to select() to correctly handle POLLHUP (Contributed by Max
Nekludov)

Additional bugfixes, name changes, and other differences as detailed in the
ChangeLog.