PIC18F2331-E/SP Microchip Technology, PIC18F2331-E/SP Datasheet - Page 47

• Manufacturer Part Number: PIC18F2331-E/SP
• Description: IC MCU FLASH 4KX16 28-DIP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F2331-E/SP

• Core Size: 8-Bit
• Program Memory Size: 8KB (4K x 16)
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, Power Control PWM, QEI, POR, PWM, WDT
• Number Of I /o: 24
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Controller Family/series: PIC18
• No. Of I/o's: 24
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 768Byte
• Cpu Speed: 40MHz
• No. Of Timers: 4
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: I3-DB18F4431 - BOARD DAUGHTER ICEPIC3AC164035 - MODULE SKT FOR 18F2X31 28SOICDVA18XP280 - DEVICE ADAPTER 18F2220 PDIP 28LD
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

3.6.1
An adjustment may be indicated when the EUSART
begins to generate framing errors, or receives data with
errors while in Asynchronous mode. Framing errors
indicate that the system clock frequency is too high –
try decrementing the value in the OSCTUNE register to
reduce the system clock frequency. Errors in data
may suggest that the system clock speed is too low –
increment OSCTUNE.
3.6.2
This technique compares system 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
is greater than expected, then the internal oscillator
block is running too fast – decrement OSCTUNE.
© 2007 Microchip Technology Inc.
EXAMPLE
EXAMPLE
–
–
EUSART
TIMERS
PIC18F2331/2431/4331/4431
Preliminary
3.6.3
A CCP module can use free-running Timer1, clocked
by the internal oscillator block and an external event
with a known period (i.e., AC power frequency). The
time
CCPRxH:CCPRxL registers and is recorded for use
later. 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, the internal oscillator block is running too fast –
decrement OSCTUNE. If the measured time is much
less than the calculated time, the internal oscillator block
is running too slow – increment OSCTUNE.
of
the
EXAMPLE
first
event
–
CCP IN CAPTURE MODE
is
captured
DS39616C-page 45
in
the