DSPIC30F4013-20I Datasheet, PDF (140/220 Pages) Microchip Technology – High-Performance, 16-Bit Digital Signal Controllers

dsPIC30F3014/4013
20.2 Oscillator Configurations
20.2.1 INITIAL CLOCK SOURCE
SELECTION
While coming out of Power-on Reset or Brown-out
Reset, the device selects its clock source based on:
a) FOS<2:0> Configuration bits that select one of
four oscillator groups,
b) and FPR<4:0> Configuration bits that select one
of 13 oscillator choices within the primary group.
The selection is as shown in Table 20-2.
20.2.2 OSCILLATOR START-UP TIMER
(OST)
In order to ensure that a crystal oscillator (or ceramic
resonator) has started and stabilized, an Oscillator
Start-up Timer is included. It is a simple 10-bit counter
that counts 1024 TOSC cycles before releasing the
oscillator clock to the rest of the system. The time-out
period is designated as TOST. The TOST time is involved
every time the oscillator has to restart (i.e., on POR,
BOR and wake-up from Sleep). The Oscillator Start-up
Timer is applied to the LP oscillator, XT, XTL, and HS
modes (upon wake-up from Sleep, POR and BOR) for
the primary oscillator.
TABLE 20-2: CONFIGURATION BIT VALUES FOR CLOCK SELECTION
Oscillator Mode
Oscillator
Source
FOS<2:0>
FPR<4:0>
OSC2
Function
ECIO w/PLL 4x PLL
1
1
1
0
1
1
0
1
I/O
ECIO w/PLL 8x PLL
1
1
1
0
1
1
1
0
I/O
ECIO w/PLL 16x PLL
1
1
1
0
1
1
1
1
I/O
FRC w/PLL 4x
PLL
1
1
1
0
0
0
0
1
I/O
FRC w/PLL 8x
PLL
1
1
1
0
1
0
1
0
I/O
FRC w/PLL 16x PLL
1
1
1
0
0
0
1
1
I/O
XT w/PLL 4x
PLL
1
1
1
0
0
1
0
1
OSC2
XT w/PLL 8x
PLL
1
1
1
0
0
1
1
0
OSC2
XT w/PLL 16x
PLL
1
1
1
0
0
1
1
1
OSC2
HS2 w/PLL 4x
PLL
1
1
1
1
0
0
0
1
OSC2
HS2 w/PLL 8x
PLL
1
1
1
1
0
0
1
0
OSC2
HS2 w/PLL 16x PLL
1
1
1
1
0
0
1
1
OSC2
HS3 w/PLL 4x
PLL
1
1
1
1
0
1
0
1
OSC2
HS3 w/PLL 8x
PLL
1
1
1
1
0
1
1
0
OSC2
HS3 w/PLL 16x PLL
1
1
1
1
0
1
1
1
OSC2
ECIO
External
0
1
1
0
1
1
0
0
I/O
XT
External
0
1
1
0
0
1
0
0
OSC2
HS
External
0
1
1
0
0
0
1
0
OSC2
EXT
External
0
1
1
0
1
0
1
1
CLKO
ERC
External
0
1
1
0
1
0
0
1
CLKO
ERCIO
External
0
1
1
0
1
0
0
0
I/O
XTL
External
0
1
1
0
0
0
0
0
OSC2
LP
Secondary
0
0
0
X
X
X
X
X (Notes 1, 2)
FRC
Internal FRC
0
0
1
X
X
X
X
X (Notes 1, 2)
LPRC
Internal LPRC 0
1
0
X
X
X
X
X (Notes 1, 2)
Note 1: OSC2 pin function is determined by (FPR<4:0>).
2: Note that OSC1 pin cannot be used as an I/O pin even if the secondary oscillator or an internal clock
source is selected at all times.
DS70138E-page 138
© 2007 Microchip Technology Inc.