Cal-(IT)2 is developing several generations of general broad application radio/networking
test platforms for wireless research and development. CalRadio I is the first generation.
It provides a simple, low-cost platform for 802.11b development from the MAC layer and up.
It accomplishes this by putting all the MAC functionality into 'C' code that runs on a DSP.
It uses the Intersil (Conexant) Prism chip set for the physical layer. Additionally, the C5471
Texas Instruments DSP contains an ARM processor that is used to host a small Open Linux
operating kernel to provide easy access to programming, downloading and display/monitoring of
data. CalRadio I functions both as a test instrument, an access point, and as a WiFi client.
The design, schematics, software, and documentation are for public use under the
conditions of the open license included as an appendix.
Support for the development was provided by Cal-(IT)2 under the direction of Ramesh Rao.
The overall design of the system and development management was by Douglas Palmer with
RF support by Don Kimball, both with Cal-(IT)2. The RF module design and initial MAC
implementation software was provided by Symbol Technologies through the
cooperation of Bob Beach and by Kamran Khojasteh. The CodeComposer software development studio
for the TI TMS320VC5471 was donated by Texas Instruments thanks to Cathy Wicks.
CalRadio I consists of three hardware components: MP Board, RF Module and enclosure, and the
software/firmware to drive it. The MP board contains all the digital processing, memory,
802.3 Ethernet interface, serial interface and
MP Board Description
- TI TMS320VC5471 ARM+ DSP (ARM7TDMI + 5410 style DSP)
- 8-bit software controlled internal status LEDs
- Power On/Off key, 2-GP keys, and reset control key
- Power management
- Operation from WallWart (Plug Transformer) (9 - 14 volt) via power connector
- Size 4" x 6" x 3"
- Four external LED indicators
- External reset pushbuttons
- RJ45 Ethernet jack
- Dismountable antennas - SMA connector
- 10/100 Ethernet Phy
- 4 channel ADC 100KSPS (TLV2541)
- 4 channel DAC 100KSPS (TLV5636)
- Jumpers on all power connections to measure current draw
- Serial port connector (external) Mini-DIN
- EMIF pins to mezzanine connector + Vcc
- 2 Mbytes static RAM - ARM side, 512KB - DSP
- 16 Mbytes SDRAM - ARM side
- 4 Mbytes Flash ROM - ARM side
- DSP Expansion connector
Datasheets, BOM, schematics and all other information required to build,
test and evaluate CalRadio 1 is found here.
CalRadio 1.0 has a complete 802.11b stack implemented on the DSP. This drives (is driven by)
the plug-in RF module. As more plug-ins are developed additional software will be added to the
DSP kernel to enable different protocols. The key value of CalRadio is that the MAC portion
is implemented in 'C' code on the DSP giving developers unprecendented access to all aspects
of the low-level stack implementation.
Operating System Software
The ARM processor on the TI TMS320VC5471 processor runs the operating system
for CalRadio 1.0. Currently we have ucLinux running as the primary OS. This version
was supplied by Cadenux.
uClinux is a derivative of Linux 2.0 kernel intended for microcontrollers without
Memory Management Units (MMUs). You can learn more about ucLinux at:
http://www.uclinux.org. A common question is:
What the difference between linux and uClinux?
The answer is:
- Poor support for multitasking
- More efficient kernel binaries and source code
- Much smaller image (uCkernel < 512 kb, uCkernel + tools < 900 kb)
uClinux comes equipped with a full TCP/IP stack, as well as support for numerous
other networking protocols. uClinux also supports the following file systems:
NFS, ext2, MS-DOS, and FAT16/32
RF Module Description
This 802.11b transceiver module was designed by Kamran Khojasteh of Symbol
Technologies. It is based upon the Maxim MAX2821 2.4GHz 802.11b Zero-IF Transceiver.
The MAX2820 is a highly integrated RF Zero-IF transceiver designed specifically
for the 802.11b (11MB/sec) DSSS applications in the 2.4-2.5GHz ISM band.
The transceiver includes all the circuitry required to implement an RF to
baseband transceiver solution; providing a fully integrated receive path,
transmit path, VCO, frequency synthesis and baseband/control interface.
Only a PA, RF switch, RF BPF and a handful of passive components are needed
to form the complete 802.11b physical layer solution. The IC completely
eliminates the need for external IF filters by implementing a direct-conversion
radio architecture and monolithic baseband filters for both receiver and transmit.
The RFIC is specifically optimized for 802.11b (11MB/sec CCK) applications.
The baseband filtering, RX & TX signal paths support the CCK modulation scheme
for BER=10-5 at the required sensitivity levels. The device is suitable for the
full range of 802.11 data rates (1, 2, 5.5,11MB/sec) at corresponding sensitivity
levels and 22MB/sec PBCC systems. The following are a list of the transceivers
- 2400-2500MHz ISM band operation
- 802.11b (11MB/sec CCK) PHY compatible
- Complete RF/IF transceiver
- Direct conversion up & down converters
- Monolithic low phase noise VCO
- Integrated baseband low-pass filters
- Integrated PLL w/ 3-wire serial interface
- Digital bias control for external PA
- Transmit power control (range > 25dB)
- Receive baseband AGC (range > 65dB)
- Complete Baseband Interface
- Digital TX/RX Mode control
- Analog receive level detection
- 90dB RX dynamic range @ 1MB/sec
- 74dB RX dynamic range @ 11MB/sec
- 0dBm transmit power (ACPR < -36dBc)
- Single +2.7V to +3.6V supply
- Shutdown mode (Icc < 10uA)
|Weight||336 gm. (12 ozs)|
|Height||5.5 cm. (2 3/16 in.)|
|Length||17.5 cm. (6 3/4 in.)|
|Width ||10.5 cm. (4 1/8 in.)|
|Oper. voltage ||9 - 14 VDC|
|Pwr. Consumption||4.0 - 6.0W Max|
|Enclosure||Aluminum Hammond Box||
Copyrights and Protection - License Agreement
To be determined.