Datasheet

© 2007 Microchip Technology Inc. DS41270E-page 41
PIC10F220/222
8.9.2 WAKE-UP FROM SLEEP
The device can wake-up from Sleep through one of the
following events:
1. An external Reset input on GP3/MCLR
/VPP pin,
when configured as MCLR
.
2. A Watchdog Timer Time-out Reset (if WDT was
enabled).
3. A change on input pin GP0, GP1 or GP3 when
wake-up on change is enabled.
These events cause a device Reset. The TO
, PD
GPWUF bits can be used to determine the cause of a
device Reset. The TO
bit is cleared if a WDT time-out
occurred (and caused wake-up). The PD
bit, which is
set on power-up, is cleared when SLEEP is invoked.
The GPWUF bit indicates a change in state while in
Sleep at pins GP0, GP1 or GP3 (since the last file or bit
operation on GP port).
8.10 Program Verification/Code
Protection
If the Code Protection bit has not been programmed,
the on-chip program memory can be read out for
verification purposes.
The first 64 locations and the last location (Reset
Vector) can be read, regardless of the code protection
bit setting.
8.11 ID Locations
Four memory locations are designated as ID locations
where the user can store checksum or other code
identification numbers. These locations are not
accessible during normal execution, but are readable
and writable during program/verify.
Use only the lower 4 bits of the ID locations and always
program the upper 8 bits as ‘1’s.
8.12 In-Circuit Serial Programming™
The PIC10F220/222 microcontrollers can be serially
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. This allows customers to manufacture boards
with unprogrammed devices and then program the
microcontroller just before shipping the product. This
also allows the most recent firmware, or a custom
firmware, to be programmed.
The devices are placed into a Program/Verify mode by
holding the GP1 and GP0 pins low while raising the
MCLR
(VPP) pin from VIL to VIHH (see programming
specification). GP1 becomes the programming clock
and GP0 becomes the programming data. Both GP1
and GP0 are Schmitt Trigger inputs in this mode.
After Reset, a 6-bit command is then supplied to the
device. Depending on the command, 16 bits of program
data are then supplied to or from the device, depending
if the command was a Load or a Read. For complete
details of serial programming, please refer to the
PIC10F220/222 Programming Specifications.
A typical In-Circuit Serial Programming connection is
shown in Figure 8-10.
FIGURE 8-10: TYPICAL IN-CIRCUIT
SERIAL
PROGRAMMING™
CONNECTION
Caution: Right before entering Sleep, read the
input pins. When in Sleep, wake up
occurs when the values at the pins
change from the state they were in at the
last reading. If a wake-up on change
occurs and the pins are not read before
re-entering Sleep, a wake-up will occur
immediately even if no pins change
while in Sleep mode.
Note: The WDT is cleared when the device
wakes from Sleep, regardless of the wake-
up source.
External
Connector
Signals
To Normal
Connections
To Normal
Connections
PIC10F22X
V
DD
VSS
MCLR/VPP
GP1
GP0
+5V
0V
V
PP
CLK
Data I/O
V
DD