From b40f186db1517616bc45693ea457dee98e39f815 Mon Sep 17 00:00:00 2001 From: patacongo Date: Tue, 21 Jun 2011 15:20:14 +0000 Subject: Prep for 6.5 release git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@3730 7fd9a85b-ad96-42d3-883c-3090e2eb8679 --- nuttx/ReleaseNotes | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 80 insertions(+), 1 deletion(-) (limited to 'nuttx/ReleaseNotes') diff --git a/nuttx/ReleaseNotes b/nuttx/ReleaseNotes index bde78a9c5a..d3e4986119 100644 --- a/nuttx/ReleaseNotes +++ b/nuttx/ReleaseNotes @@ -1901,4 +1901,83 @@ This release also includes some completed but untest functionality. testing. Unfortunately, testing will be delayed due to tool issues. * Support for the NXP LPC315x MCUs. -Additional miscellaneous enhancements and bug fixes to task_delete(), recvfrom(), and other changes as noted in the ChangeLog. +Additional miscellaneous enhancements and bug fixes to task_delete(), recvfrom(), +and other changes as noted in the ChangeLog. + +nuttx-6.5 +^^^^^^^^^ + +The 72nd release of NuttX, Version 6.5, was made on June 21, 2011 and is +available for download from the SourceForge website. The 6.5 release +is all about support for the Atmel 8-bit AVR family. I have been +interested in the AVR family for some time but because of the severe +SRAM constraints and because of the availability of many tiny schedulers +for the AVR, it has not been "on the radar screen." However, I have +recently become interested because of interest expressed by members of +the forum and because of the availability of newer, larger capacity AVR +parts (that I don't have yet). + +This release includes support for the following AVR boards. As with any +initial support for new architectures, there are some incomplete areas +and a few caveats that need to be stated. Here they are, ordered from +the least to the most complete: + + * SoC Robotics Amber Web Server (ATMega128). + + This port of NuttX to the Amber Web Server from SoC Robotics + (http://www.soc-robotics.com/index.htm). Is only partially in place. + The Amber Web Server is based on an Atmel ATMega128 (128Kb FLASH + but only 4Kb of SRAM). + + STATUS: Work on this port has stalled due to toolchain issues. It + is complete, but untested. + + * Micropendous 3 AT9USB647 + + This port of NuttX to the Opendous Micropendous 3 board. The + Micropendous3 may be populated with an AT90USB646, 647, 1286, or + 1287. See http://code.google.com/p/opendous/. I have only the + AT90USB647 version for testing. This version has very limited + memory resources: 64Kb of FLASH and 4Kb of SRAM. + + STATUS: The basic port was released in NuttX-6.5. This basic port + consists only of a "Hello, World!!" example that demonstrates + initialization of the OS, creation of a simple task, and serial + console output. The tiny SRAM limits what you can do with the + AT90USB647 (see issues below). + + * PJRC Teensy++ 2.0 AT9USB1286 + + This is a port of NuttX to the PJRC Teensy++ 2.0 board. This board + was developed by PJRC (http://pjrc.com/teensy/). The Teensy++ 2.0 is + based on an Atmel AT90USB1286 MCU with 128Kb of FLASH and 8Kb of SRAM; + a little more room to move than the AT90USB647. + + STATUS: The basic port was released in NuttX-6.5. This basic port + consists of a "Hello, World!!" example and also slightly simplified + NuttShell (NSH) configuration (see the NSH User Guide at + http://www.nuttx.org/NuttShell.html). + + An SPI driver and a USB device driver exist for the AT90USB as well + as a USB mass storage configuration. However, this configuration is not + fully debugged as of the NuttX-6.5 release. + +AVR-specific issues. The basic AVR port is solid and biggest issue for using +AVR is its tiny SRAM memory and its Harvard architecture. Because of the +Harvard architecture, constant data that resides to flash is inaccessible using +"normal" memory reads and writes (only SRAM data can be accessed "normally"). +Special AVR instructions are available for accessing data in FLASH, but these +have not been integrated into the normal, general purpose OS. + +Most NuttX test applications are console-oriented with lots of strings used +for printf and debug output. These strings are all stored in SRAM now due to +these data accessing issues and even the smallest console-oriented applications +can quickly fill a 4-8Kb memory. So, in order for the AVR port to be useful, +one of two things would need to be done: + +1. Don't use console applications that required lots of strings. The basic + AVR port is solid and your typical deeply embedded application should work + fine. + +2. Create a special version of printf that knows how to access strings that + reside in FLASH (or EEPROM). -- cgit v1.2.3