PIC18LF8490-I/PT Microchip Technology, PIC18LF8490-I/PT Datasheet - Page 44

• Manufacturer Part Number: PIC18LF8490-I/PT
• Description: IC,MICROCONTROLLER,8-BIT,PIC CPU,CMOS,TQFP,80PIN,PLASTIC
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18LF8490-I/PT

• Rohs Compliant: YES
• 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: 66
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TFQFP
• Processor Series: PIC18LF
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: SPI, I2C, EUSART, AUSART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 66
• Number Of Timers: 1 x 8
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DV164136, DM163028
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

PIC18F6390/6490/8390/8490
3.1.3
The length of the transition between clock sources is
the sum of two cycles of the old clock source and three
to four cycles of the new clock source. This formula
assumes that the new clock source is stable.
Three bits indicate the current clock source and its
status. They are:
• OSTS (OSCCON<3>)
• IOFS (OSCCON<2>)
• T1RUN (T1CON<6>)
In general, only one of these bits will be set while in a
given power-managed mode. When the OSTS bit is
set, the primary clock is providing the device clock.
When the IOFS bit is set, the INTOSC output provides
a stable, 8 MHz clock source to a divider that actually
drives the device clock. When the T1RUN bit is set, the
Timer1 oscillator provides the clock. If none of these
bits are set, then either the INTRC clock source clocks
the device, or the INTOSC source is not yet stable.
If the internal oscillator block is configured as the
primary
Configuration bits, then both the OSTS and IOFS bits
may be set when in PRI_RUN or PRI_IDLE modes.
This indicates that the primary clock (INTOSC output)
is generating a stable 8 MHz output. Entering another
power-managed RC mode at the same frequency
would clear the OSTS bit.
3.1.4
The power-managed mode that is invoked with the
SLEEP instruction is determined by the setting of the
IDLEN bit at the time the instruction is executed. If
another SLEEP instruction is executed, the device will
enter the power-managed mode specified by IDLEN at
that time. If IDLEN has changed, the device will enter
the new power-managed mode specified by the new
setting.
DS39629C-page 42
Note 1: Caution should be used when modifying a
2: Executing a SLEEP instruction does not
clock
CLOCK TRANSITIONS AND
STATUS INDICATORS
MULTIPLE SLEEP COMMANDS
single IRCF bit. If V
possible to select a higher clock speed
than is supported by the low V
Improper device operation may result if
the V
necessarily place the device into Sleep
mode. It acts as the trigger to place the
controller into either the Sleep mode or
one of the Idle modes, depending on the
setting of the IDLEN bit.
DD
source
/F
OSC
specifications are violated.
by
DD
the
is less than 3V, it is
FOSC3:FOSC0
DD
.
3.2
In the Run modes, clocks to both the core and
peripherals are active. The difference between these
modes is the clock source.
3.2.1
The PRI_RUN mode is the normal, full-power
execution mode of the microcontroller. This is also the
default mode upon a device Reset unless Two-Speed
Start-up is enabled (see Section 23.3 “Two-Speed
Start-up” for details). In this mode, the OSTS bit is set.
The IOFS bit may be set if the internal oscillator block
is the primary clock source (see Section 2.7.1
“Oscillator Control Register”).
3.2.2
The SEC_RUN mode is the compatible mode to the
“clock switching” feature offered in other PIC18
devices. In this mode, the CPU and peripherals are
clocked from the Timer1 oscillator. This gives users the
option of lower power consumption while still using a
high-accuracy clock source.
SEC_RUN mode is entered by setting the SCS1:SCS0
bits to ‘01’. The device clock source is switched to the
Timer1 oscillator (see Figure 3-1), the primary
oscillator is shut down, the T1RUN bit (T1CON<6>) is
set and the OSTS bit is cleared.
On transitions from SEC_RUN mode to PRI_RUN, the
peripherals and CPU continue to be clocked from the
Timer1 oscillator while the primary clock is started.
When the primary clock becomes ready, a clock switch
back to the primary clock occurs (see Figure 3-2).
When the clock switch is complete, the T1RUN bit is
cleared, the OSTS bit is set and the primary clock
provides the clock. The IDLEN and SCS bits are not
affected by the wake-up; the Timer1 oscillator
continues to run.
Note:
Run Modes
PRI_RUN MODE
SEC_RUN MODE
The Timer1 oscillator should already be
running prior to entering SEC_RUN mode.
If the T1OSCEN bit is not set when the
SCS1:SCS0 bits are set to ‘01’, entry to
SEC_RUN mode will not occur. If the
Timer1 oscillator is enabled, but not yet
running, peripheral clocks will be delayed
until the oscillator has started. In such
situations, initial oscillator operation is far
from stable and unpredictable operation
may result.
© 2007 Microchip Technology Inc.