
PIC10F200/202/204/206
DS41239D-page 42
2007 Microchip Technology Inc.
9.2
Oscillator Configurations
9.2.1
OSCILLATOR TYPES
The PIC10F200/202/204/206 devices are offered with
Internal Oscillator mode only.
INTOSC: Internal 4 MHz Oscillator
9.2.2
INTERNAL 4 MHz OSCILLATOR
The internal oscillator provides a 4 MHz (nominal) system
clock (see
Section 12.0 “Electrical Characteristics”
for
information on variation over voltage and temperature).
In addition, a calibration instruction is programmed into
the last address of memory, which contains the calibra-
tion value for the internal oscillator. This location is
always uncode protected, regardless of the code-pro-
tect settings. This value is programmed as a
MOVLW xx
instruction where
xx
is the calibration value and is
placed at the Reset vector. This will load the W register
with the calibration value upon Reset and the PC will
then roll over to the users program at address 0x000.
The user then has the option of writing the value to the
OSCCAL Register (05h) or ignoring it.
OSCCAL, when written to with the calibration value, will
“trim” the internal oscillator to remove process variation
from the oscillator frequency.
9.3
Reset
The device differentiates between various kinds of
Reset:
Power-on Reset (POR)
MCLR Reset during normal operation
MCLR Reset during Sleep
WDT time-out Reset during normal operation
WDT time-out Reset during Sleep
Wake-up from Sleep on pin change
Wake-up from Sleep on comparator change
Some registers are not reset in any way, they are
unknown on POR and unchanged in any other Reset.
Most other registers are reset to “Reset state” on
Power-on Reset (POR), MCLR, WDT or Wake-up on
pin change Reset during normal operation. They are
not affected by a WDT Reset during Sleep or MCLR
Reset during Sleep, since these Resets are viewed as
resumption of normal operation. The exceptions to this
are TO, PD, GPWUF and CWUF bits. They are set or
cleared differently in different Reset situations. These
bits are used in software to determine the nature of
Reset. See Table 9-1 for a full description of Reset
states of all registers.
TABLE 9-1:
RESET CONDITIONS FOR REGISTERS – PIC10F200/202/204/206
Note:
Erasing the device will also erase the pre-
programmed internal calibration value for
the internal oscillator. The calibration
value must be read prior to erasing the
part so it can be reprogrammed correctly
later.
Register
Address
Power-on Reset
MCLR Reset, WDT Time-out,
Wake-up On Pin Change, Wake on
Comparator Change
W
—
qqqq qqqu
(1)
xxxx xxxx
xxxx xxxx
1111 1111
qqqq qqqu
(1)
uuuu uuuu
uuuu uuuu
1111 1111
q00q quuu
(2)
qq0q quuu
(2)
INDF
00h
TMR0
01h
PCL
02h
STATUS
03h
00-1 1xxx
STATUS
(3)
03h
00-1 1xxx
FSR
04h
111x xxxx
1111 1110
---- xxxx
111u uuuu
uuuu uuuu
---- uuuu
OSCCAL
05h
GPIO
06h
CMCON
(3)
07h
1111 1111
1111 1111
---- 1111
uuuu uuuu
1111 1111
---- 1111
OPTION
—
TRISGPIO
—
Legend:
Note 1:
u
= unchanged,
x
= unknown, – = unimplemented bit, read as ‘
0
’,
q
= value depends on condition.
Bits <7:2> of W register contain oscillator calibration values due to
MOVLW XX
instruction at top of memory.
See Table 9-2 for Reset value for specific conditions.
PIC10F204/206 only.
2:
3: