ATMEGA8-16PC Atmel, ATMEGA8-16PC Datasheet - Page 31

• Manufacturer Part Number: ATMEGA8-16PC
• Description: IC AVR MCU 8K 16MHZ COM 28-DIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8-16PC

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 6x10b
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: ATMEGA816PC

Oscillator Calibration
Register – OSCCAL
2486Z–AVR–02/11
• 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. During Reset, the 1MHz calibration value which is located
in the signature row High byte (address 0x00) is automatically loaded into the OSCCAL Regis-
ter. If the internal RC is used at other frequencies, the calibration values must be loaded
manually. This can be done by first reading the signature row by a programmer, and then store
the calibration values in the Flash or EEPROM. Then the value can be read by software and
loaded into the OSCCAL Register. When OSCCAL is zero, the lowest available frequency is
chosen. Writing non-zero values to this register will increase the frequency of the Internal Oscil-
lator. Writing 0xFF 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 frequency. Otherwise, the EEPROM or Flash write may fail.
Note that the Oscillator is intended for calibration to 1.0MHz, 2.0MHz, 4.0MHz, or 8.0MHz. Tun-
ing to other values is not guaranteed, as indicated in
Table 11. Internal RC Oscillator Frequency Range
Bit
Read/Write
Initial Value
OSCCAL Value
0xFF
0x00
0x7F
CAL7
R/W
7
Min Frequency in Percentage of
CAL6
R/W
6
Nominal Frequency (%)
CAL5
R/W
5
Device Specific Calibration Value
100
50
75
CAL4
R/W
4
CAL3
R/W
3
Table
Max Frequency in Percentage of
CAL2
R/W
2
Nominal Frequency (%)
11.
CAL1
R/W
1
100
150
200
CAL0
R/W
ATmega8(L)
0
OSCCAL
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