User's Manual

MOD090-HP
User’s Manual
PAGE 4
Technical support [phone] www.avalanwireless.com
Technical Summary
The MOD090 module allows you to build your own extreme-range, non-line-of-
sight, point-to-multipoint wireless solution. The module uses the new technology in
our 900Mhz and is fully FCC/IC certied for quick integration with no RF retesting
required.
The MOD090 solution offers the ideal combination of the maximum allowed transmit
power and unbeatable interference immunity in conjunction with high throughput
and validated encryption.
The host microcontroller is responsible for conguring the keys that the MOD090-HP
uses for RF communication/encryption, as well as transferring data to and from the
MOD090-HP. The MOD090-HP features an 8kB transmit FIFO and a 5kB receive FIFO.
The RF communication topology that the modules use is a point to multipoint star
topology. There is one RF master Access Point (AP) and up to 63 RF slave Subscriber
Units (SU).
Data from the AP can be sent to one specic SU or broadcast to all SUs. Broadcast
data has no retransmissions and is not guaranteed to reach all SUs. Data from an SU
is always sent to the AP with retransmissions.
Data is divided up into blocks for RF transmission. This division of the data allows
for better interference immunity and re-transmission performance.
The digital interface to the MOD090-HP may be SPI or UART, depending upon which
rmware is running in the MOD090-HP.
Serial Peripheral Interface (SPI) is a full duplex synchronous serial interface. SPI is
a master-slave interface, with the master providing the synchronous clock.
Universal Asynchronous Receiver/Transmitter (UART) is an asynchronous serial
interface that allows data to be transmitted without a clock signal, but the sender
and receiver of the data must agree in advance on the timing parameters and spe-
cial bits are added to each data byte to synchronize the sending and receiving units.
Selecting SPI or UART:
The choice of interface is up to the user and governed by the user's application and
the nature of the host microcontroller. UART is more common, being closely related
to RS-232. It is also places fewer demands on the host microcontroller. The UART
interface is limited to 115,200 bits per second, while SPI may be run as high as 12
megabits per second. Whether the MOD090-HP uses SPI or UART is a choice that is
controlled at boot up. By connecting a 10K resistor from Pin 8 (Error Flag) to Vcc
(pull up), the MOD090-HP will boot up in UART mode. If the resistor is connected
instead to ground (pull down), it will boot up in SPI mode.