PIC18LF8490-I/PT Microchip Technology, PIC18LF8490-I/PT Datasheet - Page 37

• 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

2.6.5.1
An adjustment may be required when the AUSART
begins to generate framing errors or receives data with
errors while in Asynchronous mode. Framing errors
indicate that the device clock frequency is too high. To
adjust for this, decrement the value in OSTUNE to
reduce the clock frequency. On the other hand, errors
in data may suggest that the clock speed is too low. To
compensate, increment OSTUNE to increase the clock
frequency.
2.6.5.2
This technique compares device clock speed to some
reference clock. Two timers may be used; one timer is
clocked by the peripheral clock, while the other is
clocked by a fixed reference source, such as the
Timer1 oscillator.
Both timers are cleared, but the timer clocked by the
reference generates interrupts. When an interrupt
occurs, the internally clocked timer is read and both
timers are cleared. If the internally clocked timer value
REGISTER 2-1:
© 2007 Microchip Technology Inc.
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7
bit 6
bit 5
bit 4-0
Note 1:
INTSRC
R/W-0
Available only in certain oscillator configurations; otherwise, this bit is unavailable and read as ‘0’. See
Section 2.6.4 “PLL in INTOSC Modes” for details.
Compensating with the AUSART
Compensating with the Timers
INTSRC: Internal Oscillator Low-Frequency Source Select bit
1 = 31.25 kHz device clock derived from 8 MHz INTOSC source (divide-by-256 enabled)
0 = 31 kHz device clock derived directly from INTRC internal oscillator
PLLEN: Frequency Multiplier PLL for INTOSC Enable bit
1 = PLL enabled for INTOSC (4 MHz and 8 MHz only)
0 = PLL disabled
Unimplemented: Read as ‘0’
TUN4:TUN0: Frequency Tuning bits
01111 = Maximum frequency
•
•
00001
00000 = Center frequency. Oscillator module is running at the calibrated frequency.
11111
•
•
10000 = Minimum frequency
PLLEN
R/W-0
OSCTUNE: OSCILLATOR TUNING REGISTER
(1)
(1)
W = Writable bit
‘1’ = Bit is set
•
•
•
•
U-0
—
PIC18F6390/6490/8390/8490
R/W-0
TUN4
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
R/W-0
is greater than expected, then the internal oscillator
block is running too fast. To adjust for this, decrement
the OSCTUNE register.
2.6.5.3
A CCP module can use free-running Timer1 (or
Timer3), clocked by the internal oscillator block and an
external event with a known period (i.e., AC power
frequency). The time of the first event is captured in the
CCPRxH:CCPRxL registers and is recorded. When the
second event causes a capture, the time of the first
event is subtracted from the time of the second event.
Since the period of the external event is known, the
time difference between events can be calculated.
If the measured time is much greater than the
calculated time, then the internal oscillator block is
running too fast. To compensate, decrement the
OSTUNE register. If the measured time is much less
than the calculated time, then the internal oscillator
block is running too slow. To compensate, increment
the OSTUNE register.
TUN3
(1)
Compensating with the Timers
R/W-0
TUN2
x = Bit is unknown
R/W-0
TUN1
DS39629C-page 35
R/W-0
TUN0
bit 0