PIC16C72-20/SP Microchip Technology, PIC16C72-20/SP Datasheet - Page 68

• Manufacturer Part Number: PIC16C72-20/SP
• Description: IC MCU OTP 2KX14 A/D PWM 28DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Cr

Specifications of PIC16C72-20/SP

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Size: 3.5KB (2K x 14)
• Program Memory Type: OTP
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 6 V
• Data Converters: A/D 5x8b
• Oscillator Type: External
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Processor Series: PIC16C
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Interface Type: I2C, SPI, SSP
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 1 x 16 bit
• Operating Supply Voltage: 2.5 V to 6 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: ICE2000, DM163022
• Minimum Operating Temperature: 0 C
• On-chip Adc: 5 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: Q858228

PIC16C72 Series
10.10
The PIC16C72/CR72 has 8 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 un-masked 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.
The RB0/INT pin interrupt, the RB port change inter-
rupt and the TMR0 overflow interrupt flags are con-
tained in the INTCON register.
The peripheral interrupt flags are contained in the spe-
cial function registers PIR1 and PIR2. The correspond-
ing interrupt enable bits are contained in special
function registers PIE1 and PIE2, and the peripheral
interrupt enable bit is contained in special function reg-
ister INTCON.
When an interrupt is responded to, 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.
FIGURE 10-11: INTERRUPT LOGIC
DS39016A-page 68
Note:
Interrupts
Individual interrupt flag bits are set regard-
less of the status of their corresponding
mask bit or the GIE bit.
ADIF
ADIE
TMR2IF
TMR2IE
SSPIF
SSPIE
CCP1IF
CCP1IE
TMR1IF
TMR1IE
Preliminary
T0IF
T0IE
INTF
INTE
RBIF
RBIE
PEIE
GIE
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. 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 or the GIE bit
10.10.1 INT INTERRUPT
External interrupt on RB0/INT pin is edge triggered:
either rising if bit INTEDG (OPTION<6>) is set, or fall-
ing, if the INTEDG bit is clear. When a valid edge
appears
(INTCON<1>) is set. This interrupt can be disabled by
clearing enable bit INTE (INTCON<4>). Flag bit INTF
must be cleared in software in the interrupt service rou-
tine before re-enabling this interrupt. The INT interrupt
can wake-up the processor from SLEEP, if bit INTE was
set prior to going into SLEEP. The status of global inter-
rupt enable bit GIE decides whether or not the proces-
sor branches to the interrupt vector following wake-up.
See Section 10.13 for details on SLEEP mode.
10.10.2 TMR0 INTERRUPT
An overflow (FFh
flag bit T0IF (INTCON<2>). The interrupt can be
enabled/disabled by setting/clearing enable bit T0IE
(INTCON<5>). (Section 4.0)
10.10.3 PORTB INTCON CHANGE
An input change on PORTB<7:4> sets flag bit RBIF
(INTCON<0>). The interrupt can be enabled/disabled
by setting/clearing enable bit RBIE (INTCON<4>).
(Section 3.2)
on
the
00h) in the TMR0 register will set
RB0/INT
Wake-up (If in SLEEP mode)
1998 Microchip Technology Inc.
Interrupt to CPU
Clear GIE bit
pin,
flag
bit
INTF