PIC12F1822 MICROCHIP [Microchip Technology], PIC12F1822 Datasheet - Page 189

• Manufacturer Part Number: PIC12F1822
• Description: 8/14-Pin Flash Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

22.0
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 provided to the MDOUT pin.
The carrier signal is comprised of two distinct and sep-
arate signals. A carrier high (CARH) signal and a car-
rier low (CARL) signal. During the time in which the
modulator (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.
FIGURE 22-1:
 2010 Microchip Technology Inc.
Comparator C2
Comparator C1
MSSP1 SDO1
MDCL<3:0>
DATA SIGNAL MODULATOR
MDCH<3:0>
MDMS<3:0>
No Channel
No Channel
No Channel
No Channel
Reserved
Reserved
EUSART
MDCIN1
MDCIN2
MDCIN1
MDCIN2
Reserved
Reserved
Selected
Reserved
MDMIN
Selected
Selected
Selected
MDBIT
CLKR
CCP1
CCP1
CLKR
CCP1
V
V
SS
SS
(1)
SIMPLIFIED BLOCK DIAGRAM OF THE DATA SIGNAL MODULATOR
0000
0001
0010
0011
0100
*
*
0000
0001
0010
0011
*
*
0000
0001
0010
0011
0100
0101
0110
*
*
1111
*
0101
0110
0111
1000
1001
1010
0011
1111
0101
0110
0111
1000
*
*
1111
CARH
MOD
CARL
MDCHPOL
MDCLPOL
MDEN
EN
PIC12F/LF1822/16F/LF1823
Note
Preliminary
1:
D
D
SYNC
SYNC
Data Signal
Modulator
PIC16F/LF1823 only.
Q
Q
MDCLSYNC
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 22-1 shows a Simplified Block Diagram of the
Data Signal Modulator peripheral.
MDCHSYNC
1
0
1
0
MDOPOL
MDOE
DS41413A-page 189
MDOUT