ATmega324PA Atmel Corporation, ATmega324PA Datasheet - Page 36

• Manufacturer Part Number: ATmega324PA
• Manufacturer: Atmel Corporation

Specifications of ATmega324PA

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 32
• Ext Interrupts: 32
• Usb Speed: No
• Usb Interface: No
• Spi: 3
• Twi (i2c): 1
• Uart: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

9.6
8272C–AVR–06/11
Calibrated Internal RC Oscillator
To find suitable load capacitance for a 32.768kHz crysal, please consult the crystal datasheet.
When this oscillator is selected, start-up times are determined by the SUT Fuses and CKSEL0
as shown in
Table 9-9.
Note:
By default, the Internal RC Oscillator provides an approximate 8MHz clock. Though voltage and
temperature dependent, this clock can be very accurately calibrated by the the user. See
28-10 on page 336
The device is shipped with the CKDIV8 Fuse programmed. See
page 39
This clock may be selected as the system clock by programming the CKSEL Fuses as shown in
Table
the pre-programmed calibration value into the OSCCAL Register and thereby automatically cal-
ibrates the RC Oscillator. The accuracy of this calibration is shown as Factory calibration in
Table 28-10 on page
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 9-10.
Notes:
Power Conditions
BOD enabled
Fast rising power
Slowly rising power
BOD enabled
Fast rising power
Slowly rising power
40, it is possible to get a higher calibration accuracy than by using the factory calibration.
9-10. If selected, it will operate with no external components. During reset, hardware loads
1. These options should only be used if frequency stability at start-up is not important for the
1. The device is shipped with this option selected.
2. If 8MHz frequency exceeds the specification of the device (depends on V
for more details.
application.
Fuse can be programmed in order to divide the internal frequency by 8.
Table
ATmega164A/PA/324A/PA/644A/PA/1284/P
Start-up Times for the Low Frequency Crystal Oscillator Clock Selection
Internal Calibrated RC Oscillator Operating Modes
Frequency Range
9-9.
and
336.
”Internal Oscillator Speed” on page 389
7.3 - 8.1
Start-up Time from
”Calibration Byte” on page
Power-down and
Reserved
Reserved
Power-save
(2)
32K CK
32K CK
32K CK
1K CK
1K CK
1K CK
(MHz)
”OSCCAL – Oscillator Calibration Register” on
Additional Delay
14CK + 4.1ms
14CK + 65ms
14CK + 4.1ms
14CK + 65ms
(V
from Reset
300.
CC
14CK
14CK
= 5.0V)
Table 28-10 on page
(1)
and
”System Clock Prescaler” on
(1)
(1)
page 441
CKSEL3..0
0010
CKSEL0
CC
0
0
0
0
1
1
1
1
(1)
), the CKDIV8
for more details.
336.
SUT1..0
00
01
10
11
00
01
10
11
Table
36