ATMEGA1284P-MUR Atmel, ATMEGA1284P-MUR Datasheet - Page 34

• Manufacturer Part Number: ATMEGA1284P-MUR
• Description: MCU AVR 128KB FLASH 20MHZ 44VQFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA1284P-MUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-VQFN Exposed Pad
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.4
8272A–AVR–01/10
Full Swing Crystal Oscillator
Table 8-4.
Notes:
This Crystal Oscillator is a full swing oscillator, with rail-to-rail swing on the XTAL2 output. This is
useful for driving other clock inputs and in noisy environments. The current consumption is
higher than the
Oscillator will only operate for Vcc = 2.7 - 5.5 volts.
Some initial guidelines for choosing capacitors for use with crystals are given in
crystal should be connected as described in
The operating mode is selected by the fuses CKSEL3..1 as shown in
Table 8-5.
Notes:
Table 8-6.
164A/164PA/324A/324PA/644A/644PA/1284/1284P
Oscillator Source /
Power Conditions
Crystal Oscillator, BOD
enabled
Crystal Oscillator, fast
rising power
Crystal Oscillator, slowly
rising power
Frequency Range
Oscillator Source /
Power Conditions
Ceramic resonator, fast
rising power
Ceramic resonator, slowly
rising power
Ceramic resonator, BOD
enabled
1. These options should only be used when not operating close to the maximum frequency of the
2. These options are intended for use with ceramic resonators and will ensure frequency stability
1. If the crystal frequency exceeds the specification of the device (depends on V
device, and only if frequency stability at start-up is not important for the application. These
options are not suitable for crystals.
at start-up. They can also be used with crystals when not operating close to the maximum fre-
quency of the device, and if frequency stability at start-up is not important for the application.
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.
0.4 - 20
Start-up Times for the Low Power Crystal Oscillator Clock Selection (Continued)
Full Swing Crystal Oscillator Operating Modes
Start-up Times for the Full Swing Crystal Oscillator Clock Selection
”Low Power Crystal Oscillator” on page
(1)
(MHz)
Start-up Time from
Start-up Time from
Power-down and
Power-down and
Power-save
Power-save
16K CK
16K CK
16K CK
258 CK
258 CK
1K CK
CKSEL3..1
011
”Clock Source Connections” on page
Additional Delay
Additional Delay
14CK + 4.1 ms
14CK + 65 ms
Recommended Range for Capacitors C1
14CK + 4.1 ms
14CK + 65 ms
(V
(V
from Reset
from Reset
CC
CC
14CK
33. Note that the Full Swing Crystal
14CK
= 5.0V)
= 5.0V)
(2)
(1)
(1)
and C2 (pF)
Table
12 - 22
CKSEL0
CKSEL0
8-5.
0
0
0
1
1
1
CC
Table
32.
), the CKDIV8
SUT1..0
SUT1..0
8-6. The
00
01
10
01
10
11
34