ATMEGA16-16AU SL602 Atmel, ATMEGA16-16AU SL602 Datasheet - Page 30

• Manufacturer Part Number: ATMEGA16-16AU SL602
• Manufacturer: Atmel

Oscillator Calibration
Register – OSCCAL
2466T–AVR–07/10
• Bits 7..0 – CAL7..0: Oscillator Calibration Value
Writing the calibration byte to this address will trim the Internal Oscillator to remove process vari-
ations from the Oscillator frequency. This is done automatically during Chip Reset. When
OSCCAL is zero, the lowest available frequency is chosen. Writing non-zero values to this regis-
ter will increase the frequency of the Internal Oscillator. Writing $FF to the register gives the
highest available frequency. The calibrated Oscillator is used to time EEPROM and Flash
access. If EEPROM or Flash is written, do not calibrate to more than 10% above the nominal fre-
quency. Otherwise, the EEPROM or Flash write may fail. Note that the Oscillator is intended for
calibration to 1.0 MHz, 2.0 MHz, 4.0 MHz, or 8.0 MHz. Tuning to other values is not guaranteed,
as indicated in
Table 11. Internal RC Oscillator Frequency Range.
Bit
Read/Write
Initial Value
OSCCAL Value
$FF
$00
$7F
CAL7
R/W
Table
7
Min Frequency in Percentage of
11.
CAL6
R/W
Nominal Frequency (%)
6
CAL5
R/W
5
100
Device Specific Calibration Value
50
75
CAL4
R/W
4
CAL3
R/W
3
Max Frequency in Percentage of
CAL2
R/W
2
Nominal Frequency (%)
CAL1
R/W
1
100
150
200
ATmega16(L)
CAL0
R/W
0
OSCCAL
30