EM77950
BB Controller
8 Baseband (BB)
8.1 BB: Standard Interface for the RFW102 Series
8.1.1 Features
Parallel interface to RFW102 modem
Serial to Parallel conversion of RFW102 interface
Input FIFO (RX_FIFO)
Output FIFO (TX_FIFO)
Preamble Correlation
Packet Address Filter (Network and unique)
CRC calculation
Working Frequencies: 6-24MHz
Power Save modes: Idle, Power-down
Inter-RFWAVES networks Carrier-sense
Discharge of the RFW-102 reference capacitor
Compensate for clock drifts between transmitting and the receiving the EM77950
up to 1000ppm. Hence, the EM77950 requires low performance crystal.
Interrupt Driver – connected to the EM77950’s internal interrupt and informs the
EM77950 about BB events.
8.1.2 Description
RFWAVES has developed a very low cost wireless modem (RFW102) for short range,
cost-sensitive applications. The modem is a physical layer element (PHY) – allowing
the transmission and reception of bits from one end to the other.
In an RFWAVES application, the MCU is in charge of the MAC layer protocol. In order
to reduce the real-time demands of the MCU handling the MAC protocol, the BB was
developed. The BB enables the MCU an easy interface to RFW102 through a parallel
interface, similar to memory access. It converts the fast serial input to 8-bit words,
which are much easier for an 8-bit MCU to work with, and requires a lower rate
oscillator. It buffers the input through a TBD bytes FIFO, enabling the MCU to access
the BB more efficiently. Instead of reading one byte per interrupt, the MCU can read up
to 16 bytes in each interrupt. This reduces the MCU overhead in reading incoming
words, insofar as stack stuffing and pipeline emptying are concerned, in cases where
each incoming byte causes an interrupt. When using the FIFO, the MCU pays the
same overhead for all the FIFO bytes as it paid for only one byte without a FIFO.
Product Specification (V1.0) 10.09.2007
(This specification is subject to change without further notice)
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ELAN [ ELAN MICROELECTRONICS CORP ]
