PIC18F6490-E/PT Microchip Technology, PIC18F6490-E/PT Datasheet - Page 38

• Manufacturer Part Number: PIC18F6490-E/PT
• Description: IC PIC MCU FLASH 16KX16 64TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F6490-E/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, LCD, POR, PWM, WDT
• Number Of I /o: 50
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 64-TFQFP
• For Use With: DM163028 - BOARD DEMO PICDEM LCD
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

PIC18F6390/6490/8390/8490
2.7
Like
PIC18F6390/6490/8390/8490 family includes a feature
that allows the device clock source to be switched from
the main oscillator to an alternate low-frequency clock
source. PIC18F6390/6490/8390/8490 devices offer
two alternate clock sources. When an alternate 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 2-8:
DS39629C-page 36
T1OSO
T1OSI
OSC2
OSC1
Clock Sources and
Oscillator Switching
previous
Primary Oscillator
Secondary Oscillator
PIC18F6390/6490/8390/8490 CLOCK DIAGRAM
PIC18
OSCCON<6:4>
Oscillator
Internal
Source
Source
INTRC
8 MHz
Block
T1OSCEN
Enable
Oscillator
Sleep
31 kHz (INTRC)
(INTOSC)
devices,
8 MHz
OSCTUNE<6>
the
PIC18F6X90/8X90
1
0
500 kHz
250 kHz
125 kHz
31 kHz
8 MHz
4 MHz
2 MHz
1 MHz
OSCCON<6:4>
register details.
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.
PIC18F6390/6490/8390/8490 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 RC0/T1OSO/T13CKI and RC1/T1OSI
pins. Like the LP Oscillator mode circuit, loading
capacitors are also connected from each pin to ground.
The Timer1 oscillator is discussed in greater detail in
Section 11.3 “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 PIC18F6390/6490/8390/8490
devices are shown in Figure 2-8. See Section 23.0
“Special Features of the CPU” for Configuration
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
© 2007 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