ST ST7538Q, Примечание к применению

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ST7538Q FSK power line transceiver description AN2744
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3 ST7538Q FSK power line transceiver description
The ST7538Q transceiver performs a half-duplex communication over the power line
network using frequency shift keying (FSK) modulation. It operates from a 7.5 to 12.5 V
single supply voltage (PAV
CC
) and integrates a differential-output power line interface (PLI)
stage and two linear regulators providing 5 V (VDC) and 3.3 V (DV
DD
).
The ST7538Q can be programmed to communicate using eight different frequency
channels (60, 66, 72, 76, 82.05, 86, 110 and 132.5 kHz), four baud rates (600, 1200, 2400
and 4800 symbols per second) and two frequency deviations (1 and 0.5).
Many auxiliary functions are integrated. The transmission section includes automatic control
on PLI output voltage and current, programmable time-out function and thermal shutdown.
The reception section includes automatic input level control, carrier/preamble detection and
band-in-use signaling.
Additional features are included, such as watchdog timer, zero-crossing detector, internal
oscillator and a general purpose op-amp.
The serial interface (configurable as UART or SPI) allows interfacing to a host
microcontroller, intended to manage the communication protocol. A reset output (RSTO)
and a programmable 4-8-16 MHz clock (MCLK) can be provided to the microcontroller to
simplify the application.
Communication on the power line can be either synchronous or asynchronous with the data
clock (CLR/T) provided by the transceiver at the programmed baud rate.
When in transmission mode (i.e. RxTx line at low level), the ST7538Q transceiver samples
the data on the TxD line, generating an FSK modulated signal on the ATO pin. The same
Figure 3. ST7538Q transceiver block diagram