PIC12F509-I/P Microchip Technology Inc., PIC12F509-I/P Datasheet - Page 45

• Manufacturer Part Number: PIC12F509-I/P
• Description: 8 PIN, 1.5 KB FLASH, 41 RAM, 6 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC12F509-I/P

• Cpu Speed: 1 MIPS
• Eeprom Memory: 0 Bytes
• Frequency: 4 MHz
• Input Output: 6
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 8-pin PDIP
• Programmable Memory: 1.5K Bytes
• Ram Size: 41 Bytes
• Speed: 4 MHz
• Timers: 1-8-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

Although the oscillator will operate with no external
capacitor (C
above 20 pF for noise and stability reasons. With no or
small external capacitance, the oscillation frequency
can vary dramatically due to changes in external
capacitances, such as PCB trace capacitance or
package lead frame capacitance.
Section 10.0 “Electrical Characteristics” shows RC
frequency variation from part-to-part due to normal
process variation. The variation is larger for larger val-
ues of R (since leakage current variation will affect RC
frequency more for large R) and for smaller values of C
(since variation of input capacitance will affect RC
frequency more).
Also, see the Electrical Specifications section for
variation of oscillator frequency due to V
R
to operating temperature for given R, C and V
values.
FIGURE 7-5:
7.2.5
The internal RC oscillator provides a fixed 4 MHz (nom-
inal) system clock at V
Section 10.0
information on variation over voltage and temperature).
© 2005 Microchip Technology Inc.
EXT
C
V
R
EXT
SS
EXT
/C
V
F
EXT
OSC
DD
/4
values, as well as frequency variation due
INTERNAL 4 MHz RC OSCILLATOR
EXT
= 0 pF), we recommend using values
“Electrical
EXTERNAL RC
OSCILLATOR MODE
OSC2/CLKOUT
OSC1
DD
N
= 5V and 25°C, (see
Characteristics”
PIC16F505
PIC12F508
PIC12F509
DD
Internal
clock
for given
Preliminary
DD
for
PIC12F508/509/16F505
In addition, a calibration instruction is programmed into
the last address of memory, which contains the calibra-
tion value for the internal RC 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.
For the PIC12F508/509/16F505 devices, only bits
<7:1> of OSCCAL are implemented. Bits CAL6-CAL0
are used for calibration. Adjusting CAL6-CAL0 from
‘0000000’ to ‘1111111’ changes the clock speed. See
Register 4-5 for more information.
Note:
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.
The 0 bit of OSCCAL is unimplemented
and should be written as ‘0’ when modify-
ing OSCCAL for compatibility with future
devices.
DS41236B-page 43