PIC16F72-I/SP Microchip Technology Inc., PIC16F72-I/SP Datasheet - Page 70

• Manufacturer Part Number: PIC16F72-I/SP
• Description: 28 PIN, 3.5 KB FLASH, 128 RAM, 22 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F72-I/SP

• A/d Inputs: 5-Channel, 8-Bit
• Cpu Speed: 5 MIPS
• Eeprom Memory: 0 Bytes
• Input Output: 22
• Interface: I2C/SPI
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SPDIP
• Programmable Memory: 3.5K Bytes
• Ram Size: 128 Bytes
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC16F72
FIGURE 11-9:
11.11 Interrupts
The PIC16F72 has up to eight sources of interrupt. The
interrupt control register (INTCON) records individual
interrupt requests in flag bits. It also has individual and
global interrupt enable bits.
A global interrupt enable bit, GIE (INTCON<7>)
enables (if set) all unmasked interrupts, or disables (if
cleared) all interrupts. When bit GIE is enabled, and an
interrupt’s flag bit and mask bit are set, the interrupt will
vector immediately. Individual interrupts can be dis-
abled through their corresponding enable bits in vari-
ous registers. Individual interrupt bits are set,
regardless of the status of the GIE bit. The GIE bit is
cleared on RESET.
The “return from interrupt” instruction, RETFIE, exits
the interrupt routine, as well as sets the GIE bit, which
re-enables interrupts.
FIGURE 11-10:
DS39597B-page 68
Note:
INTERNAL RESET
PWRT TIME-OUT
INTERNAL POR
OST TIME-OUT
Individual interrupt flag bits are set, regard-
less of the status of their corresponding
mask bit, or the GIE bit.
TMR2IF
TMR2IE
ADIF
ADIE
MCLR
CCP1IF
CCP1IE
TMR1IF
TMR1IE
SSPIF
SSPIE
V
DD
SLOW RISE TIME (MCLR TIED TO V
INTERRUPT LOGIC
0V
T
PWRT
TMR0IF
TMR0IE
INTF
INTE
RBIF
RBIE
PEIE
GIE
1V
5V
The RB0/INT pin interrupt, the RB port change interrupt
and the TMR0 overflow interrupt flags are contained in
the INTCON register.
The peripheral interrupt flags are contained in the
Special Function Register, PIR1. The corresponding
interrupt enable bits are contained in Special Function
Register, PIE1, and the peripheral interrupt enable bit
is contained in Special Function Register INTCON.
When an interrupt is serviced, the GIE bit is cleared to
disable any further interrupt, the return address is
pushed onto the stack, and the PC is loaded with
0004h. Once in the Interrupt Service Routine, the
source(s) of the interrupt can be determined by polling
the interrupt flag bits. The interrupt flag bit(s) must be
cleared in software before re-enabling interrupts to
avoid recursive interrupts.
For external interrupt events, such as the INT pin or
PORTB change interrupt, the interrupt latency will be
three or four instruction cycles. The exact latency
depends when the interrupt event occurs, relative to
the current Q cycle. The latency is the same for one or
two cycle instructions. Individual interrupt flag bits are
set, regardless of the status of their corresponding
mask bit, PEIE bit, or the GIE bit.
DD
THROUGH RC NETWORK)
T
OST
Wake-up (If in SLEEP mode)
 2002 Microchip Technology Inc.
Interrupt to CPU