ATMEGA3250P-20AUR Atmel, ATMEGA3250P-20AUR Datasheet - Page 34

• Manufacturer Part Number: ATMEGA3250P-20AUR
• Description: MCU AVR 32K FLASH 20MHZ 100TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA3250P-20AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 69
• 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: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.7
34
External Clock
ATmega325P/3250P
When this Oscillator is selected, start-up times are determined by the SUT Fuses as shown in
Table 8-9 on page
Table 8-9.
Note:
To drive the device from an external clock source, XTAL1 should be driven as shown in
3. To run the device on an external clock, the CKSEL Fuses must be programmed to “0000”.
Figure 3. External Clock Drive Configuration
When this clock source is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 1. Crystal Oscillator Clock Frequency
Table 2. Start-up Times for the External Clock Selection
When applying an external clock, it is required to avoid sudden changes in the applied clock fre-
quency to ensure stable operation of the MCU. A variation in frequency of more than 2% from
Power Conditions
BOD enabled
Fast rising power
Slowly rising power
CKSEL3..0
0000
SUT1..0
00
01
10
11
2.
1. The device is shipped with this option selected
Start-up Time from Power-
Start-up times for the internal calibrated RC Oscillator clock selection
down and Power-save
34.
6 CK
6 CK
6 CK
EXTERNAL
SIGNAL
CLOCK
Start-up Time from Power-
down and Power-save
NC
Reserved
Frequency Range
0 - 16 MHz
6 CK
6 CK
6 CK
Additional Delay from
Reset (V
Reserved
14CK + 4.1 ms
14CK + 65 ms
.
XTAL2
XTAL1
GND
14CK
CC
= 5.0V)
Additional Delay from
Reset (V
14CK + 65 ms
14CK + 4.1 ms
14CK
CC
BOD enabled
Fast rising power
Slowly rising power
Recommended Usage
= 5.0V)
(1)
8023F–AVR–07/09
SUT1..0
00
01
10
11
Figure