© 2004 Microchip Technology Inc. DS70054C-page 7-15
Section 7. Oscillator
Oscillator
7
7.9.1 External RC Oscillator with I/O Enabled
The ERCIO Oscillator mode functions in the exact same manner as the ERC Oscillator mode.
The only difference is that the OSC2 pin is configured as an I/O pin.
As in the RC mode, the user needs to take into account any variation of the clock frequency due
to tolerance of external R
EXT and CEXT components used, process variation, voltage and
temperature. Figure 7-8 shows how the RC with the I/O pin combination is connected.
Figure 7-8: ERCIO Oscillator Mode
7.9.2 External RC Start-up
There is no start-up delay associated with the RC oscillator. Oscillation will begin when VDD is
applied.
7.9.3 RC Operating Frequency
The following graphs show the external RC oscillator frequency as a function of device voltage
for a selection of RC component values.
I/O (OSC2)
CEXT
REXT
VSS
OSC1
Internal
Clock
VDD
dsPIC30F
Note: The user should verify that VDD is within specifications before the device begins to
execute code.
Note: The following graphs should be used only as approximate guidelines for RC
component selection. The actual frequency will vary based on the system
temperature and device. Please refer to the specific device data sheet for further
RC oscillator characteristic data.
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