ATMEGA325-16AI Atmel, ATMEGA325-16AI Datasheet - Page 30

• Manufacturer Part Number: ATMEGA325-16AI
• Description: IC AVR MCU 32K 16MHZ 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA325-16AI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

8.6
2570M–AVR–04/11
External Clock
This clock may be selected as the system clock by programming the CKSEL Fuses as shown in
Table 8-7 on page
hardware loads the pre-programmed calibration value into the OSCCAL Register and thereby
automatically calibrates the RC Oscillator. The accuracy of this calibration is shown as Factory
calibration in
By changing the OSCCAL register from SW, see
page
The accuracy of this calibration is shown as User calibration in
When this Oscillator is used as the chip clock, the Watchdog Oscillator will still be used for the
Watchdog Timer and for the Reset Time-out. For more information on the pre-programmed cali-
bration value, see the section
Table 8-7.
Note:
When this Oscillator is selected, start-up times are determined by the SUT Fuses as shown in
Table 8-8 on page
Table 8-8.
Note:
To drive the device from an external clock source, XTAL1 should be driven as shown in
8-3 on page
to “0000” (see
Table 8-9.
Power Conditions
BOD enabled
Fast rising power
Slowly rising power
32, it is possible to get a higher calibration accuracy than by using the factory calibration.
1. The device is shipped with this option selected.
2. The frequency ranges are preliminary values. Actual values are TBD.
3. If 8MHz frequency exceeds the specification of the device (depends on V
The device is shipped with this option selected.
Fuse can be programmed in order to divide the internal frequency by 8.
31. To run the device on an external clock, the CKSEL Fuses must be programmed
Table 27-2 on page
Frequency Range
Internal Calibrated RC Oscillator Operating Modes
Start-up times for the internal calibrated RC Oscillator clock selection
Table 8-9 on page
Crystal Oscillator Clock Frequency
Frequency Range
30.
30. If selected, it will operate with no external components. During reset,
0 - 16MHz
7.3 - 8.1
Start-up Time from Power-
down and Power-save
“Calibration Byte” on page
(2)
300.
30).
(MHz)
Reserved
6 CK
6 CK
6 CK
ATmega325/3250/645/6450
“OSCCAL – Oscillator Calibration Register” on
Additional Delay from
Reset (V
268.
14CK + 65ms
14CK + 4.1ms
14CK
Table 27-2 on page
CC
(1)(3)
CKSEL3..0
CKSEL3..0
= 5.0V)
0000
0010
(Note:)
CC
SUT1..0
), the CKDIV8
00
01
10
11
300.
Figure
30