PIC16F874A-I/PT Microchip Technology, PIC16F874A-I/PT Datasheet - Page 158

• Manufacturer Part Number: PIC16F874A-I/PT
• Description: IC MCU FLASH 4K 20MHZ 44-TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F874A-I/PT

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 44-TQFP, 44-VQFP
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 33
• Eeprom Size: 128 x 8
• Ram Size: 192 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 192 B
• Interface Type: I2C/SPI/USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 33
• Number Of Timers: 3
• 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
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163022, DV164120
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• 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: Lead free / RoHS Compliant

PIC16F87XA
14.14 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 high-impedance).
For lowest current consumption in this mode, place all
I/O pins at either V
circuitry is drawing current from the I/O pin, power-
down the A/D and disable external clocks. Pull all I/O
pins that are high-impedance inputs, high or low
externally, to avoid switching currents caused by
floating inputs. The T0CKI input should also be at V
or
contribution from on-chip pull-ups on PORTB should
also be considered.
The MCLR pin must be at a logic high level (V
14.14.1
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 execu-
tion 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.
9.
10. Comparator output changes state.
Other peripherals cannot generate interrupts since
during Sleep, no on-chip clocks are present.
DS39582B-page 156
V
External Reset input on MCLR pin.
Watchdog Timer wake-up (if WDT was enabled).
Interrupt from INT pin, RB port change or
peripheral interrupt.
PSP read or write (PIC16F874/877 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).
EEPROM write operation completion.
SS
for
WAKE-UP FROM SLEEP
lowest
DD
current
or V
SS
, ensure no external
consumption.
IHMC
2
C).
The
).
DD
When the SLEEP instruction is being executed, the next
instruction (PC + 1) is prefetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be set (enabled). Wake-up is
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 inter-
rupt address (0004h). In cases where the execution of
the instruction following SLEEP is not desirable, the
user should have a NOP after the SLEEP instruction.
14.14.2
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
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
instruction should be executed before a SLEEP
instruction.
SLEEP instruction, the SLEEP instruction will
complete 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.
execution of a SLEEP instruction, the device will
immediately 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
 2003 Microchip Technology Inc.