DSPIC30F6012 MICROCHIP [Microchip Technology], DSPIC30F6012 Datasheet - Page 150

• Manufacturer Part Number: DSPIC30F6012
• Description: High-Performance, 16-Bit Digital Signal Controllers
• Manufacturer: MICROCHIP [Microchip Technology]

dsPIC30F6011/6012/6013/6014
20.2
20.2.1
While coming out of Power-on Reset or Brown-out
Reset, the device selects its clock source based on:
a)
b)
The selection is as shown in Table 20-2.
TABLE 20-2:
20.2.2
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 T
oscillator clock to the rest of the system. The time-out
period is designated as T
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.
DS70117F-page 148
EC
ECIO
EC w/ PLL 4x
EC w/ PLL 8x
EC w/ PLL 16x
ERC
ERCIO
XT
XT w/ PLL 4x
XT w/ PLL 8x
XT w/ PLL 16x
XTL
HS
LP
FRC
LPRC
Note 1:
FOS<1:0> Configuration bits that select one of
four oscillator groups,
and FPR<3:0> Configuration bits that select one
of 13 oscillator choices within the primary group.
Oscillator Mode
2:
Oscillator Configurations
OSC2 pin function is determined by the Primary Oscillator mode selection (FPR<3:0>).
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.
INITIAL CLOCK SOURCE
SELECTION
OSCILLATOR START-UP TIMER
(OST)
CONFIGURATION BIT VALUES FOR CLOCK SELECTION
OSC
cycles before releasing the
Primary
Primary
Primary
Primary
Primary
Primary
Primary
Primary
Primary
Primary
Primary
Primary
Primary
Secondary
Internal FRC
Internal LPRC
OST
Oscillator
Source
. The T
OST
FOS1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
1
time is
FOS0
1
1
1
1
1
1
1
1
1
1
1
1
1
0
1
0
20.2.3
Enabling the LP oscillator is controlled with two
elements:
1.
2.
The LP oscillator is on (even during Sleep mode) if
LPOSCEN = 1. The LP oscillator is the device clock if:
• COSC<1:0> = 00 (LP selected as main oscillator)
• LPOSCEN = 1
Keeping the LP oscillator on at all times allows for a fast
switch to the 32 kHz system clock for lower power oper-
ation. Returning to the faster main oscillator will still
require a start-up time.
FPR3
and
—
—
—
1
1
1
1
1
1
1
0
0
0
0
0
0
The current oscillator group bits COSC<1:0>.
The LPOSCEN bit (OSCON register).
FPR2
LP OSCILLATOR CONTROL
—
—
—
0
1
1
1
1
0
0
1
1
1
1
0
0
FPR1
—
—
—
1
0
0
1
1
0
0
0
0
1
1
0
1
© 2006 Microchip Technology Inc.
FPR0
—
—
—
1
0
1
0
1
1
0
0
1
0
1
X
X
(Notes 1, 2)
(Notes 1, 2)
(Notes 1, 2)
Function
OSC2
CLKO
CLKO
OSC2
OSC2
OSC2
OSC2
OSC2
OSC2
I/O
I/O
I/O
I/O
I/O