ATmega1284P Atmel Corporation, ATmega1284P Datasheet - Page 33

• Manufacturer Part Number: ATmega1284P
• Manufacturer: Atmel Corporation

Specifications of ATmega1284P

• Flash (kbytes): 128 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): 16
• Eeprom (bytes): 4096
• 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

9.3
8272C–AVR–06/11
Low Power Crystal Oscillator
This Crystal Oscillator is a low power oscillator, with reduced voltage swing on the XTAL2 out-
put. It gives the lowest power consumption, but is not capable of driving other clock inputs, and
may be more susceptible to noise in noisy environments. In these cases, refer to the
Crystal Oscillator” on page
Some initial guidelines for choosing capacitors for use with crystals are given in
crystal should be connected as described in
The Low Power Oscillator can operate in three different modes, each optimized for a specific fre-
quency range. The operating mode is selected by the fuses CKSEL3..1 as shown in
Table 9-3.
Notes:
The CKSEL0 Fuse together with the SUT1..0 Fuses select the start-up times as shown in
9-4.
Table 9-4.
Oscillator Source /
Power Conditions
Ceramic resonator, fast
rising power
Ceramic resonator, slowly
rising power
Ceramic resonator, BOD
enabled
Ceramic resonator, fast
rising power
Ceramic resonator, slowly
rising power
Crystal Oscillator, BOD
enabled
Crystal Oscillator, fast
rising power
Crystal Oscillator, slowly
rising power
Frequency Range (MHz)
1. If the crystal frequency exceeds the specification of the device (depends on V
2. This is the recommended CKSEL settings for the different frequency ranges.
3. This option should not be used with crystals, only with ceramic resonators.
Fuse can be programmed in order to divide the internal frequency by 8. It must be ensured
that the resulting divided clock meets the frequency specification of the device.
8.0 - 16.0
ATmega164A/PA/324A/PA/644A/PA/1284/P
0.4 - 0.9
0.9 - 3.0
3.0 - 8.0
Low Power Crystal Oscillator Operating Modes
Start-up Times for the Low Power Crystal Oscillator Clock Selection
34.
Start-up Time from
Power-down and
Power-save
258 CK
258 CK
16K CK
16K CK
16K CK
1K CK
1K CK
1K CK
CKSEL3..1
100
101
110
111
”Clock Source Connections” on page
(3)
(2)
Additional Delay
Recommended Range for Capacitors C1
14CK + 4.1ms
14CK + 4.1ms
14CK + 65ms
14CK + 65ms
14CK + 4.1ms
14CK + 65ms
(V
from Reset
CC
14CK
14CK
= 5.0V)
(1)
(2)
(1)
(2)
(1)
(2)
and C2 (pF)
12 - 22
12 - 22
12 - 22
–
CKSEL0
0
0
0
0
1
1
1
1
CC
Table
32.
), the CKDIV8
Table
”Full Swing
SUT1..0
9-3. The
00
01
10
11
00
01
10
11
Table
9-3.
33