PIC18F4580T-I/PT Microchip Technology, PIC18F4580T-I/PT Datasheet - Page 51

• Manufacturer Part Number: PIC18F4580T-I/PT
• Description: IC PIC MCU FLASH 16KX16 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F4580T-I/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: CAN, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 36
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 1.5K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 11x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

5.5
PIC18F2480/2580/4480/4580
three separate on-chip timers that help regulate the
Power-on Reset process. Their main function is to
ensure that the device clock is stable before code is
executed. These timers are:
• Power-up Timer (PWRT)
• Oscillator Start-up Timer (OST)
• PLL Lock Time-out
5.5.1
The Power-up Timer (PWRT) of the PIC18F2480/2580/
4480/4580 devices is an 11-bit counter which uses the
INTRC source as the clock input. This yields an
approximate time interval of 2048 x 32 μs = 65.6 ms.
While the PWRT is counting, the device is held in
Reset.
The power-up time delay depends on the INTRC clock
and will vary from chip-to-chip due to temperature and
process variation. See DC parameter 33 for details.
The PWRT is enabled by clearing the PWRTEN
Configuration bit.
5.5.2
The Oscillator Start-up Timer (OST) provides a
1024 oscillator cycle (from OSC1 input) delay after the
PWRT delay is over (parameter 33). This ensures that
the crystal oscillator or resonator has started and
stabilized.
The OST time-out is invoked only for XT, LP, HS and
HSPLL modes and only on Power-on Reset or on exit
from most power-managed modes.
TABLE 5-2:
© 2009 Microchip Technology Inc.
HSPLL
HS, XT, LP
EC, ECIO
RC, RCIO
INTIO1, INTIO2
Note 1:
Configuration
2:
Oscillator
Device Reset Timers
66 ms (65.5 ms) is the nominal Power-up Timer (PWRT) delay.
2 ms is the nominal time required for the PLL to lock.
POWER-UP TIMER (PWRT)
OSCILLATOR START-UP TIMER
(OST)
TIME-OUT IN VARIOUS SITUATIONS
66 ms
66 ms
(1)
devices
PWRTEN = 0
+ 1024 T
(1)
66 ms
66 ms
66 ms
+ 1024 T
incorporate
Power-up
OSC
(1)
(1)
(1)
PIC18F2480/2580/4480/4580
+ 2 ms
OSC
(2)
(2)
and Brown-out
5.5.3
With the PLL enabled in its PLL mode, the time-out
sequence following a Power-on Reset is slightly differ-
ent from other oscillator modes. A separate timer is
used to provide a fixed time-out that is sufficient for the
PLL to lock to the main oscillator frequency. This PLL
lock time-out (T
oscillator start-up time-out.
5.5.4
On power-up, the time-out sequence is as follows:
1.
2.
The total time-out will vary based on oscillator configu-
ration and the status of the PWRT. Figure 5-3,
Figure 5-4, Figure 5-5, Figure 5-6 and Figure 5-7 all
depict time-out sequences on power-up, with the
Power-up Timer enabled and the device operating in
HS Oscillator mode. Figures 5-3 through 5-6 also apply
to devices operating in XT or LP modes. For devices in
RC mode and with the PWRT disabled, on the other
hand, there will be no time-out at all.
Since the time-outs occur from the POR pulse, if MCLR
is kept low long enough, all time-outs will expire. Bring-
ing MCLR high will begin execution immediately
(Figure 5-5). This is useful for testing purposes or to
synchronize more than one PIC18FXXXX device
operating in parallel.
1024 T
PWRTEN = 1
After the POR pulse has cleared, PWRT
time-out is invoked (if enabled).
Then, the OST is activated.
1024 T
OSC
—
—
—
PLL LOCK TIME-OUT
TIME-OUT SEQUENCE
+ 2 ms
OSC
PLL
(2)
) is typically 2 ms and follows the
Power-Managed Mode
1024 T
1024 T
Exit from
DS39637D-page 51
OSC
—
—
—
+ 2 ms
OSC
(2)