Vault 7: Projects
This publication series is about specific projects related to the Vault 7 main publication.
© 2009 Microchip Technology Inc. DS39700C-page 6-13
Section 6. Oscillator
Oscillator
6
6.5 PRIMARY OSCILLATOR (POSC)
The Primary Oscillator is available on the OSC1 and OSC2 pins of the PIC24F family. In general,
the Primary Oscillator can be configured for an external clock input or an external crystal. Further
details of the Primary Oscillator operating modes are described in subsequent sections. The
Primary Oscillator has up to 6 operating modes, summarized in Table 6-2.
Table 6-2: Primary Oscillator Operating Modes
The POSCMD and FNOSC Configuration bits (Configuration Word 2<1:0> and <10:8>, respec-
tively) select the operating mode of the Primary Oscillator. The POSCMD<1:0> bits select the
particular submode to be used (XT, HS or EC), while the FNOSC<2:0> bits determine if the
oscillator will be used by itself or with the internal PLL. The PIC24F operates from the Primary
Oscillator whenever the COSC bits (OSCCON<14:12>) are set to ‘010’ or ‘011’.
Refer to the “Electrical Characteristics” section in the specific device data sheet for further
information regarding frequency range for each crystal mode.
Figure 6-3: Crystal or Ceramic Resonator Operation (XT or HS Oscillator Mode)
Oscillator
Mode
Description
OSC2 Pin
Function
EC External clock input (0-32 MHz) F
OSC/2
ECPLL External clock input (4-48 MHz), PLL enabled FOSC/2, Note 2
HS 10 MHz-32 MHz crystal Note 1
HSPLL 10 MHz-32 MHz crystal Note 2
XT 3.5 MHz-10 MHz crystal Note 1
XTPLL 3.5 MHz-8 MHz crystal, PLL enabled Note 1
Note 1: External crystal connected to OSC1 and OSC2 in these modes.
2: Available only in devices with special PLL blocks (such as the 96 MHz PLL); the
basic 4x PLL block generates clock frequencies beyond the device’s operating
range.
C1
(3)
C2
(3)
XTAL
OSC2
R
S
(1)
OSC1
RF
(2)
Sleep
To Internal Logic
PIC24F
Note 1: A series resistor, Rs, may be required for AT strip cut crystals.
2: The internal feedback resistor, R
F, is typically in the range of 2 to 10 MΩ.
3: See Section 6.5.2.4 “Determining the Best Values for Oscillator Components”.
Protego_Release_01_05-Related-OEM-Documentation-PIC24FJ32MC10X-Reference_Manual-Section6-Oscillator.pdf