16F84A Microchip Technology, 16F84A Datasheet - Page 32

• Manufacturer Part Number: 16F84A
• Description: 18-pin Enhanced Flash/EEPROM 8-Bit Microcontroller
• Manufacturer: Microchip Technology

PIC16F84A
6.11.3
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.
6.12
If
programmed, the on-chip program memory can be
read out for verification purposes.
6.13
Four memory locations (2000h - 2004h) are designated
as ID locations to store checksum or other code
identification numbers. These locations are not
accessible during normal execution but are readable
and writable only during program/verify. Only the
four least significant bits of ID location are usable.
DS35007A-page 32
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.
Note:
the
WAKE-UP USING INTERRUPTS
Program Verification/Code Protection
ID Locations
code
Microchip does not recommend code pro-
tecting windowed devices.
protection
bit(s)
have
not
been
Preliminary
6.14
PIC16F84A
programmed while in the end application circuit. This is
simply done with two lines for clock and data, and three
other lines for power, ground, and the programming
voltage. Customers can manufacture boards with
unprogrammed devices, and then program the
microcontroller just before shipping the product,
allowing the most recent firmware or custom firmware
to be programmed.
For complete details of serial programming, please
refer to the In-Circuit Serial Programming (ICSP™)
Guide, (DS30277).
In-Circuit Serial Programming
microcontrollers
1998 Microchip Technology Inc.
can
be
serially