AC162078 Microchip Technology, AC162078 Datasheet - Page 26

• Manufacturer Part Number: AC162078
• Description: HEADER INTRFC MPLAB ICD2 18F1330
• Manufacturer: Microchip Technology

Specifications of AC162078

• Accessory Type: Transition Header
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: ICD2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Not applicable / Not applicable

PIC18F1230/1330
3.7
Like previous PIC18 devices, the PIC18F1230/1330
family includes a feature that allows the device clock
source to be switched from the main oscillator to an
alternate low-frequency clock source. PIC18F1230/1330
devices offer two alternate clock sources. When an alter-
nate clock source is enabled, the various power-managed
operating modes are available.
Essentially, there are three clock sources for these
devices:
• Primary oscillators
• Secondary oscillators
• Internal oscillator block
The primary oscillators include the External Crystal
and Resonator modes, the External RC modes, the
External Clock modes and the internal oscillator block.
The particular mode is defined by the FOSC3:FOSC0
Configuration bits. The details of these modes are
covered earlier in this chapter.
FIGURE 3-8:
DS39758D-page 26
T1OSO
T1OSI
OSC2
OSC1
Clock Sources and Oscillator
Switching
Primary Oscillator
Secondary Oscillator
PIC18F1230/1330 CLOCK DIAGRAM
OSCCON<6:4>
Oscillator
Internal
Source
Source
INTRC
8 MHz
T1OSCEN
Enable
Oscillator
Block
Sleep
31 kHz (INTRC)
(INTOSC)
8 MHz
OSCTUNE<6>
1
0
500 kHz
250 kHz
125 kHz
31 kHz
8 MHz
4 MHz
2 MHz
1 MHz
OSCCON<6:4>
The secondary oscillators are those external sources
not connected to the OSC1 or OSC2 pins. These
sources may continue to operate even after the
controller is placed in a power-managed mode.
PIC18F1230/1330 devices offer the Timer1 oscillator
as a secondary oscillator. This oscillator, in all power-
managed modes, is often the time base for functions
such as a real-time clock.
Most often, a 32.768 kHz watch crystal is connected
between the T1OSO/T1CKI and T1OSI pins. Like the
LP mode oscillator circuit, loading capacitors are also
connected from each pin to ground. The Timer1 oscil-
lator is discussed in greater detail in Section 13.2
“Timer1 Oscillator”.
In addition to being a primary clock source, the internal
oscillator block is available as a power-managed
mode clock source. The INTRC source is also used as
the clock source for several special features, such as
the WDT and Fail-Safe Clock Monitor.
The clock sources for the PIC18F1230/1330 devices
are shown in Figure 3-8. See Section 20.0 “Special
Features of the CPU” for Configuration register details.
OSCTUNE<7>
111
110
101
100
011
010
001
000
4 x PLL
HSPLL, INTOSC/PLL
LP, XT, HS, RC, EC
Internal Oscillator
FOSC3:FOSC0
T1OSC
 2009 Microchip Technology Inc.
Clock Source Option
for Other Modules
WDT, PWRT, FSCM
and Two-Speed Start-up
Control
Clock
OSCCON<1:0>
Peripherals
IDLEN
CPU