PIC16F74-I/L Microchip Technology Inc., PIC16F74-I/L Datasheet - Page 104

• Manufacturer Part Number: PIC16F74-I/L
• Description: 44 PIN, 7 KB FLASH, 192 RAM, 33 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F74-I/L

• A/d Inputs: 8-Channel, 8-Bit
• Cpu Speed: 5 MIPS
• Eeprom Memory: 0 Bytes
• Input Output: 33
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 44-pin PLCC
• Programmable Memory: 7K Bytes
• Ram Size: 192 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

PIC16F7X
12.14 Power-down Mode (SLEEP)
Power-down mode is entered by executing a SLEEP
instruction.
If enabled, the Watchdog Timer will be cleared but
keeps running, the PD bit (STATUS<3>) is cleared, the
TO (STATUS<4>) bit is set, and the oscillator driver is
turned off. The I/O ports maintain the status they had
before the SLEEP instruction was executed (driving
high, low, or hi-impedance).
For lowest current consumption in this mode, place all
I/O pins at either V
cuitry is drawing current from the I/O pin, power-down
the A/D and disable external clocks. Pull all I/O pins
that are hi-impedance inputs, high or low externally, to
avoid switching currents caused by floating inputs. The
T0CKI input should also be at V
current consumption. The contribution from on-chip
pull-ups on PORTB should also be considered.
The MCLR pin must be at a logic high level (V
12.14.1
The device can wake-up from SLEEP through one of
the following events:
1.
2.
3.
External MCLR Reset will cause a device RESET. All
other events are considered a continuation of program
execution and cause a "wake-up". The TO and PD bits
in the STATUS register can be used to determine the
cause of device RESET. The PD bit, which is set on
power-up, is cleared when SLEEP is invoked. The TO
bit is cleared if a WDT time-out occurred and caused
wake-up.
The following peripheral interrupts can wake the device
from SLEEP:
1.
2.
3.
4.
5.
6.
7.
8.
Other peripherals cannot generate interrupts, since
during SLEEP, no on-chip clocks are present.
DS30325B-page 102
External RESET input on MCLR pin.
Watchdog
enabled).
Interrupt from INT pin, RB port change or a
Peripheral Interrupt.
PSP read or write (PIC16F74/77 only).
TMR1 interrupt. Timer1 must be operating as
an asynchronous counter.
CCP Capture mode interrupt.
Special event trigger (Timer1 in Asynchronous
mode, using an external clock).
SSP (START/STOP) bit detect interrupt.
SSP transmit or receive in Slave mode
(SPI/I
USART RX or TX (Synchronous Slave mode).
A/D conversion (when A/D clock source is RC).
2
C).
WAKE-UP FROM SLEEP
Timer
DD
or V
wake-up
SS
, ensure no external cir-
DD
(if
or V
WDT
SS
for lowest
IHMC
was
).
When the SLEEP instruction is being executed, the next
instruction (PC + 1) is pre-fetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be set (enabled). Wake-up
occurs, regardless of the state of the GIE bit. If the GIE
bit is clear (disabled), the device continues execution at
the instruction after the SLEEP instruction. If the GIE bit
is set (enabled), the device executes the instruction
after the SLEEP instruction and then branches to the
interrupt address (0004h). In cases where the execu-
tion of the instruction following SLEEP is not desirable,
the user should have a NOP after the SLEEP instruction.
12.14.2
When global interrupts are disabled (GIE cleared) and
any interrupt source has both its interrupt enable bit
and interrupt flag bit set, one of the following will occur:
• If the interrupt occurs before the execution of a
• If the interrupt occurs during or after the execu-
Even if the flag bits were checked before executing a
SLEEP instruction, it may be possible for flag bits to
become set before the SLEEP instruction completes. To
determine whether a SLEEP instruction executed, test
the PD bit. If the PD bit is set, the SLEEP instruction
was executed as a NOP.
To ensure that the WDT is cleared, a CLRWDT instruc-
tion should be executed before a SLEEP instruction.
SLEEP instruction, the SLEEP instruction will com-
plete as a NOP. Therefore, the WDT and WDT
postscaler will not be cleared, the TO bit will not
be set and PD bits will not be cleared.
tion of a SLEEP instruction, the device will imme-
diately wake-up from SLEEP. The SLEEP
instruction will be completely executed before the
wake-up. Therefore, the WDT and WDT
postscaler will be cleared, the TO bit will be set
and the PD bit will be cleared.
WAKE-UP USING INTERRUPTS
 2002 Microchip Technology Inc.