PIC10F200/202/204/206
9.2
Oscillator Configurations
9.3
Reset
The device differentiates between various kinds of
Reset:
9.2.1
OSCILLATOR TYPES
The PIC10F200/202/204/206 devices are offered with
Internal Oscillator mode only.
• Power-on Reset (POR)
• MCLR Reset during normal operation
• MCLR Reset during Sleep
• INTOSC: Internal 4 MHz Oscillator
• 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
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.
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.
OSCCAL, when written to with the calibration value, will
“trim” the internal oscillator to remove process variation
from the oscillator frequency.
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.
TABLE 9-1:
RESET CONDITIONS FOR REGISTERS – PIC10F200/202/204/206
MCLR Reset, WDT Time-out,
Wake-up On Pin Change, Wake on
Comparator Change
Register
Address
Power-on Reset
(1)
(1)
W
—
qqqq qqqu
qqqq qqqu
INDF
TMR0
PCL
00h
01h
02h
xxxx xxxx
xxxx xxxx
1111 1111
uuuu uuuu
uuuu uuuu
1111 1111
(2)
STATUS
03h
03h
00-1 1xxx
00-1 1xxx
q00q quuu
(3)
(2)
STATUS
qq0q quuu
FSR
04h
05h
06h
111x xxxx
1111 1110
---- xxxx
111u uuuu
uuuu uuuu
---- uuuu
OSCCAL
GPIO
(3)
CMCON
07h
—
1111 1111
1111 1111
---- 1111
uuuu uuuu
1111 1111
---- 1111
OPTION
TRISGPIO
—
Legend: u= unchanged, x= unknown, – = unimplemented bit, read as ‘0’, q= value depends on condition.
Note 1: Bits <7:2> of W register contain oscillator calibration values due to MOVLW XXinstruction at top of memory.
2: See Table 9-2 for Reset value for specific conditions.
3: PIC10F204/206 only.
DS41239D-page 42
© 2007 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
