464
SAM4CP [DATASHEET]
43051E–ATPL–08/14
27.8.1.4 Analog Front End control
27.8.1.4.1 Gain control
This block implements an Automatic Gain Control (AGC) which attenuates the PLC input signal via activating some out-
puts of the PPLC, so there is no saturation and therefore no distortion in the OFDM signal.
There are 6 outputs of the PPLC controlled by this peripheral. AGC0, AGC1, AGC2, AGC3, AGC4 and AGC5. Please
see reference design for further information and recommended external circuitry values.
27.8.1.4.2 TxRx control
This block modifies the configuration of the external Analog Front End by means of TXRX outputs. There are two TXRX
outputs, one for each TXDRV. These digital outputs are used to modify external filter conditions between transmission
and reception. To allow different external circuitry topologies, the polarity of both signals can be inverted by hardware
(see
“TXRX Polarity Selector Register”
).
Figure 27-9.
TxRx control block diagram
See reference design for further information about TxRx control.
27.8.1.5 Carrier Detection
Looking for an easy detection of incoming messages, the PRIME specification defines a carrier detection algorithm that
shall be based on preamble detection and header recognition. PPLC implements by hardware a set of detection
techniques to control access to medium, thus improving frame synchronization in reception and decreasing collision ratio
in transmission.
27.8.2 PHY parameters
A complete description of the PRIME PHY Layer can be found in PRIME specification. Please refer to the PRIME speci-
fication provided by the PRIME Alliance in www.prime-alliance.org
PRIME specifies a complete set of primitives to manage the PHY Layer, and the PHY-SAP (PHY Service Access Point)
from MAC layer. Doc43048 “Atmel PRIME Implementation” integrates all these functions, making them transparent to the
final user and simplifying the management.
PPLC
Analog
Front - End
Control
Gain
Control
Emiter
Control
T
TxRx Control
T
AGC [0:5]
EMIT [0:5]
EMIT [6:11]
TXRX0
TXRX1
External
Analog
Front - End