| Teeny module runs new ".NET Embedded" software stack |
Dec. 10, 2004
 A small startup in Microsoft's backyard is poised to begin shipping a tiny, 32-pin chip-like computer module that runs ".NET Embedded," a new Microsoft embedded software platform developed for use in watches and other "smart personal objects." The module, developed by startup .netcpu Corp., incorporates portions of Microsoft's Smart Personal Objects Technology (SPOT) hardware and software.
What's SPOT?
 Not wanting to limit its horizons to desktops and servers running Windows XP, or PDAs and smartphones running Windows CE (and its Windows Mobile variants), Microsoft developed SPOT to allow its software to be used more pervasively. The technology was unveiled by Bill Gates nearly two years ago, and has since become the basis of a series of consumer SPOT wristwatch products from leading watch makers, such as the Suunto watch shown here.
SPOT represents a set of hardware and software technologies capable of being embedded in "watches, accessories, peripherals, display surfaces, appliances, everyday objects, personals, mobiles, sensors/actuators, and toys," said Donald Thompson, software architect and former development manager for SPOT. SPOT's overall goal is to "increase the usefulness of everyday objects that we can wear, carry, or that might be scattered throughout the environment, ultimately making some activity easier and/or more enjoyable," Thompson added.
Stan and Ollie
Microsoft's SPOT hardware, developed in partnership with National Semiconductor and first deployed in SPOT wristwatches, primarily consists of "Stan," a radio chip that contains a tiny, sensitive 100MHz RF receiver, and "Ollie," a system-on-chip (SoC) processor based on a RISC CPU with on-chip SRAM and ROM, timers, interrupt controllers, and other core system functions.
The tiny (2.8 x 2.8 x .86 mm) radio chip draws just 90 milliwatts during operation, and a mere 30 microwatts in standby mode. Ollie, the SPOT SoC, contains a 32-bit ARM7 TDMI-S processor core which zooms along at 27.6 MHz, drawing roughly 50 mW (1.8 mW/MHz) at that blinding speed. The processor also contains 512KB of on-chip ROM and 384KB of on-chip SRAM memory. Now you know why SPOT's hardware doesn't run Windows CE, which typically uses 10 to 20 times that much memory.
Look Ma, no OS!
SPOT's embedded software stack, called .NET Embedded, includes the three blocks shaded blue in the architecture diagram below: bootstrap code, to initialize the system on powerup; a Tiny HAL (hardware abstraction layer) plus device drivers, to control the underlying system hardware; and a Tiny CLR (common language routine), through which the device is programmed.
".NET Embedded" (shaded blue) includes Tiny CLR, Tiny HAL, drivers, bootloader
The Tiny CLR implements a subset of the .NET Common Language Runtime (CLR), enabling SPOT devices to run high-level code written using a subset of the .NET Framework, a Java-like runtime environment (the .NET Framework subset for Windows CE is known as .NET Compact Framework).
The Tiny CLR, which occupies under 132KB of memory, contains enough functionality to be suitable for embedded device applications and is programmable and debugable using Visual Studio.NET (C#), according to Thompson.
"We support a subset of the .NET Framework," Thompson said. "We provide hundreds of different objects and thousands of functions. We support all of the things one would expect, like threads, strings, numeric types, datetime, fonts, bitmaps, etc. We have several domain-specific object libraries for the watch and .netcpu [CPU Module] (VTU, PWM, LCD, I/O, IRQs), among others."
.NET Embedded also provides a Tiny HAL that implements system-level functions, which interface with the system's underlying hardware, and a bootloader. The Tiny HAL takes up less than 40KB of memory.
But note: "SPOT doesn't have an OS, just enough ASM/C/C++ to support the TinyCLR," Thompson added.
Development hardware
 Early in SPOT's lifecycle, Microsoft hinted at a board-level implementation of SPOT suitable for use by hobbyists, educators, and researchers. That vision will soon become a reality, when .netcpu Corp. begins shipping the first board-level SPOT-based products next week.
The computer module is implemented in the format of a 32-pin "DIP" (dual inline package) chip, allowing the module to conveniently plug into a standard 32-pin DIP socket. In addition to the Ollie SoC, the ".netcpu CPU Module" integrates 4MB of nonvolatile Flash memory (interfaced via an SPI interface on the SoC). It also provides 24 general purpose digital I/O lines, which are multiplexed with other functions including 8 VTU ports, a USB port, two serial ports, and SPI and I2C interfaces.
A photo of the module with callouts that indicate the location of key components on the tiny assembly is available here.
.netcpu Corp is also offering a carrier board, pictured below, making it even easier to use the CPU module. The carrier board provides a 32-pin DIP socket for the CPU module, and routes signals from the CPU module's 32-pin interface to various connectors that provide easy access for experiments and projects. Other types of carrier board will be offered, according to .netcpu Corp.
.netcpu carrier board
(Click image for larger view)
The CPU module plugs into the upper right-hand corner of the carrier board, and a 9V battery can be added in the upper left-hand corner. Much of the rest of the carrier board is occupied by header connectors that provide easy access to signals coming from the CPU module. Other functions included on the carrier board include an RS-232 serial interface, 3.3- and 5-volt power supplies, a pair of DC-to-DC converters, buffers chips for signal translations, various driver chips, and a reset switch.
 The .netcpu Starter Kit includes the following, according to .netcpu Corp.: - .netcpu CPU Module
- .netcpu Carrier Board
- Microsoft .NET Embedded SDK Installer CD (including Visual Studio tools, help files, and sample applications)
- Microsoft Visual Studio 2005 Beta 1 Installer CD
- User documentation
- 9-volt unregulated linear power supply
- DIP programming shunts (jumpers)
- Custom serial cable
The kit will be available starting Dec. 15th, and is priced at just under $500, the company says.
A CPU Module kit that includes the CPU Module, Microsoft .NET Embedded SDK, Microsoft Visual Studio 2005 Beta 1 Installer CD, and user documentation -- but not a carrier board -- will be offered by the end of the year, priced at just under $200.
A future "educational" kit will include a 16x2 character LCD along with a supporting LCD device driver, according to product manager Daniel Coughlin. The included software stack does not provide user interface (UI) functions -- these need to be developed by the users of the modules and other third party developers, Coughlin adds. Users of the modules can also interface other types of LCDs using the I/O signals available, but would need to create their own device drivers to interface with the displays.
The modules can be ordered direct from .netcpu Corp.'s website.
Related Stories:
(Click here for further information)
|
|
|
news feed
