DSPIC30F2023-30I-PT Datasheet, PDF (209/286 Pages) Microchip Technology – 28/44-Pin High-Performance Switch Mode Power Supply Digital Signal Controllers

dsPIC30F1010/202X
18.4 PRIMARY OSCILLATOR ON OSC1/
OSC2 PINS:
The primary oscillator uses is shown in Figure 18-3.
FIGURE 18-3:
PRIMARY OSCILLATOR
C1
XTAL
OSC1/CLKI
Rs ⁽¹⁾
C2
OSC2/CLKO
RF ⁽²⁾
To CLKGEN
CLKO/RC15
Note 1: A series resistor, Rs, may be required for AT strip cut crystals.
2: The feedback resistor, RF, is typically in the range of 2 to 10 MΩ.
18.5 EXTERNAL CLOCK INPUT
Two of the primary Oscillator modes use an external
clock. These modes are EC and EC with IO.
In the EC mode (Figure 18-4), the OSC1 pin can be
driven by CMOS drivers. In this mode, the OSC1 pin is
high-impedance and the OSC2 pin is the clock output
(FOSC/2). This output clock is useful for testing or
synchronization purposes.
In the EC with IO mode (Figure 18-5), the OSC1 pin
can be driven by CMOS drivers. In this mode, the
OSC1 pin is high-impedance and the OSC2 pin
becomes a general purpose I/O pin. The feedback
device between OSC1 and OSC2 is turned off to save
current.
FIGURE 18-4:
EXTERNAL CLOCK INPUT OPERATION (EC OSCILLATOR CONFIGURATION)
Clock from Ext System
FOSC/2
OSC1
dsPIC30F
OSC2
FIGURE 18-5:
EXTERNAL CLOCK INPUT OPERATION (ECIO OSCILLATOR CONFIGURATION)
Clock from Ext System
I/O
OSC1
dsPIC30F
I/O (OSC2)
© 2006 Microchip Technology Inc.
Preliminary
DS70178C-page 207