DSPIC30F3013-30I Datasheet, PDF (126/210 Pages) Microchip Technology – High-Performance, 16-bit Digital Signal Controllers

dsPIC30F2011/2012/3012/3013
17.2 Oscillator Configurations
17.2.1 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 15 oscillator choices within the primary group.
The selection is as shown in Table 17-2.
17.2.2 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 17-2: CONFIGURATION BIT VALUES FOR CLOCK SELECTION
Oscillator Mode
Oscillator
Source
FOS<2:0>
FPR<4:0>
OSC2
Function
ECIO w/PLL 4x
PLL
11101101
I/O
ECIO w/PLL 8x
PLL
11101110
I/O
ECIO w/PLL 16x
PLL
11101111
I/O
FRC w/PLL 4X
PLL
11100001
I/O
FRC w/PLL 8x
PLL
11101010
I/O
FRC w/PLL 16x
PLL
11100011
I/O
XT w/PLL 4x
PLL
11100101
OSC2
XT w/PLL 8x
PLL
11100110
OSC2
XT w/PLL 16x
PLL
11100111
OSC2
HS2 w/PLL 4x
PLL
11110001
OSC2
HS2 w/PLL 8x
PLL
11110010
OSC2
HS2 w/ PLL 16x
PLL
11110011
OSC2
HS3 w/PLL 4x
PLL
11110101
OSC2
HS3 w/PLL 8x
PLL
11110110
OSC2
HS3 w/PLL 16x
PLL
11110111
OSC2
ECIO
XT
External
External
01101100
01100100
I/O
OSC2
HS
External
01100010
OSC2
EC
External
01101011
CLKO
ERC
External
01101001
CLKO
ERCIO
External
01101000
I/O
XTL
External
01100000
OSC2
LP
Secondary
0
0
0
X
X
X
X
X
(Note 1, 2)
FRC
Internal FRC 0
0
1
X
X
X
X
X
(Note 1, 2)
LPRC
Internal LPRC 0
1
0
X
X
X
X
X
(Note 1, 2)
Note 1: The OSC2 pin is either usable as a general purpose I/O pin or is completely unusable, depending on the
Primary Oscillator mode selection (FPR<4:0>).
2: 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.
DS70139G-page 126
© 2010 Microchip Technology Inc.