PIC18F4220-I/PT Microchip Technology, PIC18F4220-I/PT Datasheet - Page 43

• Manufacturer Part Number: PIC18F4220-I/PT
• Description: IC MCU FLASH 2KX16 A/D 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F4220-I/PT

• Core Size: 8-Bit
• Program Memory Size: 4KB (2K x 16)
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 36
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 13x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Controller Family/series: PIC18
• No. Of I/o's: 36
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 512Byte
• Cpu Speed: 40MHz
• No. Of Timers: 4
• Core: PIC
• Processor Series: PIC18F
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 40 MHz
• Data Ram Size: 512 B
• Data Rom Size: 256 B
• On-chip Adc: Yes
• Number Of Programmable I/os: 36
• Number Of Timers: 2 x 8 bit
• Operating Supply Voltage: 2 V to 5.5 V
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 13
• Height: 1 mm
• Interface Type: SPI, I2C, USART
• Length: 10 mm
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4.2 V
• Width: 10 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT44PT3 - SOCKET TRAN ICE 44MQFP/TQFPAC164305 - MODULE SKT FOR PM3 44TQFP444-1001 - DEMO BOARD FOR PICMICRO MCUAC164020 - MODULE SKT PROMATEII 44TQFP
• Lead Free Status / Rohs Status: Details

3.6.1
An adjustment may be indicated when the USART
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 ref-
erence 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 – USART
EXAMPLE – TIMERS
PIC18F2220/2320/4220/4320
3.6.3
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 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.
EXAMPLE – CCP IN CAPTURE
MODE
DS39599G-page 41