PIC18LF8621-I/PT Microchip Technology, PIC18LF8621-I/PT Datasheet - Page 89

• Manufacturer Part Number: PIC18LF8621-I/PT
• Description: IC PIC MCU FLASH 32KX16 80TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18LF8621-I/PT

• Core Size: 8-Bit
• Program Memory Size: 64KB (32K x 16)
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 69
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 3.8K x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 16x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TFQFP
• Controller Family/series: PIC18
• No. Of I/o's: 70
• Eeprom Memory Size: 1024Byte
• Ram Memory Size: 3840Byte
• Cpu Speed: 40MHz
• No. Of Timers: 5
• Processor Series: PIC18LF
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 3840 B
• Interface Type: MSSP, SPI, I2C, EUSART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 69
• Number Of Timers: 2 x 8 bit
• 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, DM183032
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 16 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

9.0
The PIC18F6525/6621/8525/8621 devices have multi-
ple interrupt sources and an interrupt priority feature
that allows each interrupt source to be assigned a high
or a low priority level. The high priority interrupt vector
is at 000008h, while the low priority interrupt vector is
at 000018h. High priority interrupt events will override
any low priority interrupts that may be in progress.
There are thirteen registers which are used to control
interrupt operation. They are:
• RCON
• INTCON
• INTCON2
• INTCON3
• PIR1, PIR2, PIR3
• PIE1, PIE2, PIE3
• IPR1, IPR2, IPR3
It is recommended that the Microchip header files
supplied with MPLAB
names in these registers. This allows the assembler/
compiler to automatically take care of the placement of
these bits within the specified register.
Each interrupt source has three bits to control its
operation. The functions of these bits are:
• Flag bit to indicate that an interrupt event
• Enable bit that allows program execution to
• Priority bit to select high priority or low priority
The interrupt priority feature is enabled by setting the
IPEN bit (RCON<7>). When interrupt priority is
enabled, there are two bits which enable interrupts
globally. Setting the GIEH bit (INTCON<7>) enables all
interrupts that have the priority bit set. Setting the GIEL
bit (INTCON<6>) enables all interrupts that have the
priority bit cleared. When the interrupt flag, enable bit
and appropriate global interrupt enable bit are set, the
interrupt will vector immediately to address 000008h or
000018h, depending on the priority level. Individual
interrupts can be disabled through their corresponding
enable bits.
 2005 Microchip Technology Inc.
occurred
branch to the interrupt vector address when the
flag bit is set
INTERRUPTS
®
IDE be used for the symbolic bit
PIC18F6525/6621/8525/8621
When the IPEN bit is cleared (default state), the
interrupt priority feature is disabled and interrupts are
compatible with PICmicro
Compatibility mode, the interrupt priority bits for each
source have no effect. INTCON<6> is the PEIE bit
which enables/disables all peripheral interrupt sources.
INTCON<7> is the GIE bit which enables/disables all
interrupt sources. All interrupts branch to address
000008h in Compatibility mode.
When an interrupt is responded to, the global interrupt
enable bit is cleared to disable further interrupts. If the
IPEN bit is cleared, this is the GIE bit. If interrupt priority
levels are used, this will be either the GIEH or GIEL bit.
High priority interrupt sources can interrupt a low
priority interrupt.
The return address is pushed onto the stack and the
PC is loaded with the interrupt vector address
(000008h or 000018h). Once in the Interrupt Service
Routine, the source(s) of the interrupt can be deter-
mined by polling the interrupt flag bits. The interrupt
flag bits must be cleared in software before re-enabling
interrupts to avoid recursive interrupts.
The “return from interrupt” instruction, RETFIE, exits
the interrupt routine and sets the GIE bit (GIEH or GIEL
if priority levels are used) which re-enables interrupts.
For external interrupt events, such as the INT pins or
the PORTB input change interrupt, the interrupt latency
will be three to four instruction cycles. The exact
latency is the same for one or two-cycle instructions.
Individual interrupt flag bits are set regardless of the
status of their corresponding enable bit or the GIE bit.
®
mid-range devices. In
DS39612B-page 87