2.7 Transmit Mode
In transmit mode EFR32 performs the following functionality:
• Automatic PA power ramping during the start and end of a frame transmit
• Programmable output power
• Optional preamble and synchronization word insertion
• Accurate transmit frame timing to support time synchronized radio protocols
• Optional Carrier Sense Multiple Access - Collision Avoidance (CSMA-CA) or Listen Before Talk (LBT) hardware support
• Integrated transmit test modes, as described in
2.8 Receive Mode
In receive mode EFR32 performs the following functionality:
• A single-ended (2.4 GHz) or differential (Sub-GHz) LNA amplifies the input RF signal. The amplified signal is then mixed to a low-IF
signal through the quadrature down-coversion mixer. Further signal filtering is performed before conversion to a digital signal
through the I/Q ADC.
• Digitally configurable receiver bandwidth from 100 Hz to 2.5 MHz
• Timing recovery on received data, including simultaneous support for two different frame synchronization words
• Automatic frequency offset compensation, to compensate for carrier frequency offset between the transmitter and receiver
• Support for a wide range of modulation formats as described in section
2.9 Data Buffering
EFR32 supports buffered transmit and receive modes through its buffer controller (BUFC), with four individually configurable buffers.
The BUFC uses the system RAM as storage, and each buffer can be individually configured with parameters such as:
• Buffer size
• Buffer interrupt thresholds
• Buffer RAM location
• Overflow and underflow detection
In receive mode, data following frame synchronization is moved directly from the demodulator to the buffer storage.
In transmit mode, data following the inserted preamble and synchronization word is moved directly from the buffer storage to the modu-
lator.
2.10 Unbuffered Data Transfer
For most system designs it is recommended to use the data buffering within EFR32 to provide a convenient user interface.
In cases where data buffering within EFR32 is not desired, it is possible to set up direct unbuffered data transfers using a single-pin or
two-pin interface on EFR32. A bit clock output is provided on the Serial Clock (SC) output pin, and a serial bitstream is provided to
EFR32 in a transmit mode and from EFR32 in a receive mode.
In unbuffered data transfer modes the hardware support provided by EFR32 to perform preamble and frame synchronization insertion
in transmit mode and detection in receive mode can still optionally be used.
2.11 Frame Format Support
EFR32 has an extensive support for frame handling in transmit and receive modes, which allows effective handling of even advanced
protocols. The support includes:
• Preamble and frame synchronization inserted into transmitted frames
• Full frame synchronization of received frames
• Simple address matching of received frames in hardware, further configurable address and frame filtering supported through se-
quencer
• Support for variable length frames
• Automated CRC calculation and verification
• Configurable bit ordering, with the most or least significant bit transmitted and received first
The frame format support is controlled by the Frame Controller (FRC).
Reference Manual
System Overview
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