mirror of
git://projects.qi-hardware.com/ben-wpan.git
synced 2024-11-05 06:16:15 +02:00
47 lines
2.0 KiB
Plaintext
47 lines
2.0 KiB
Plaintext
IEEE 802.15.4 Low-Rate Wireless Personal Area Network (WPAN)
|
|
============================================================
|
|
|
|
|
|
IEEE 802.15.4 defines physical layers and a media access control for
|
|
wireless networks. ZigBee and 6loWPAN are based on IEEE 802.15.4.
|
|
|
|
This project aims to add experimental WPAN functionality to the Ben
|
|
NanoNote, in order to permit evaluation of overall network performance
|
|
and to examine possible integration into future devices.
|
|
|
|
This work is licensed under the terms detailed in the file COPYING.
|
|
|
|
|
|
Hardware history
|
|
----------------
|
|
|
|
IEEE 802.15.4 transceiver chips are available from several manufacturers,
|
|
including Atmel, Freescale, and Texas Instruments. These chips are similar
|
|
in size, functionality, and cost. The first prototype of this project was
|
|
based on the Atmel AT86RF230.
|
|
|
|
The initial plan was to place the RF module on the left side of the LCD
|
|
module of the Ben NanoNote, replacing part of the display's PCB. When
|
|
installed in the Ben, the transceiver would connect directly via SPI to
|
|
the Jz4720. For development, a SiLabs C8051F326 microcontroller
|
|
implemented a USB to SPI conversion.
|
|
|
|
Then Rikard Lindstrom came up with the idea of using the Ben's 8:10 card
|
|
slot as a general expansion interface, which led to the idea of making
|
|
a WPAN card in that form factor, with the benefit of being readily usable
|
|
with any Ben already in existence.
|
|
|
|
Thus the project was split in two parts: the atben card that had only the
|
|
transceiver chip and would be used with the Ben, and the atusb card that
|
|
would be similar to the original design but abandoned its clear physical
|
|
separation of USB and RF.
|
|
|
|
Meanwhile, an improved version of the AT86RF230, the AT86RF231, became
|
|
available and the designs were updated for it. It also turned out that
|
|
the clock from the Ben was too noisy to be used as a clock source for
|
|
the transceiver. Therefore, a crystal was added to the atben design.
|
|
|
|
Finally, the SiLabs C8051F326 was replaced by an ATmega32U2, mainly
|
|
because the latter has a larger Flash memory and greater community
|
|
acceptance.
|