PIC18F26K80-I Datasheet, PDF (195/622 Pages) Microchip Technology – 28/40/44/64-Pin, Enhanced Flash Microcontrollers with ECAN™ and nanoWatt XLP Technology

PIC18F66K80 FAMILY
12.0 DATA SIGNAL MODULATOR
Note: The Data Signal Modulator is only available
on 64-pin devices (PIC18F6XK80).
The Data Signal Modulator (DSM) is a peripheral which
allows the user to mix a data stream, also known as a
modulator signal, with a carrier signal to produce a
modulated output.
Both the carrier and the modulator signals are supplied
to the DSM module, either internally from the output of
a peripheral, or externally through an input pin.
The modulated output signal is generated by perform-
ing a logical “AND” operation of both the carrier and
modulator signals and then it is provided to the MDOUT
pin.
The carrier signal is comprised of two distinct and sepa-
rate signals: a carrier high (CARH) signal and a carrier
low (CARL) signal. During the time in which the modula-
tor (MOD) signal is in a logic high state, the DSM mixes
the carrier high signal with the modulator signal. When
the modulator signal is in a logic low state, the DSM
mixes the carrier low signal with the modulator signal.
Using this method, the DSM can generate the following
types of key modulation schemes:
• Frequency-Shift Keying (FSK)
• Phase-Shift Keying (PSK)
• On-Off Keying (OOK)
Additionally, the following features are provided within
the DSM module:
• Carrier Synchronization
• Carrier Source Polarity Select
• Carrier Source Pin Disable
• Programmable Modulator Data
• Modulator Source Pin Disable
• Modulated Output Polarity Select
• Slew Rate Control
Figure 12-1 shows a simplified block diagram of the
Data Signal Modulator peripheral.
 2010-2012 Microchip Technology Inc.
DS39977F-page 195