ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 31

• Manufacturer Part Number: ATmega32U4
• Manufacturer: Atmel Corporation

Specifications of ATmega32U4

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 14
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 26
• Ext Interrupts: 13
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 3.3
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 12
• Input Capture Channels: 2
• Pwm Channels: 8
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

6.4
7766F–AVR–11/10
Low Frequency Crystal Oscillator
Table 6-4.
Notes:
Table 6-5.
Note:
The device can utilize a 32.768 kHz watch crystal as clock source by a dedicated Low Fre-
quency Crystal Oscillator. The crystal should be connected as shown in
Oscillator is selected, start-up times are determined by the SUT Fuses and CKSEL0 as shown in
Table
Table 6-6.
Oscillator Source /
Power Conditions
Ceramic resonator,
slowly rising power
Crystal Oscillator, BOD
enabled
Crystal Oscillator, fast
rising power
Crystal Oscillator,
slowly rising power
Power Conditions
BOD enabled
Fast rising power
Slowly rising power
Power Conditions
BOD enabled
Fast rising power
Slowly rising power
BOD enabled
Fast rising power
Slowly rising power
6-6.
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.
The device is shipped with this option selected.
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.
Start-up Times for the Low Power Crystal Oscillator Clock Selection (Continued)
Start-up times for the internal calibrated RC Oscillator clock selection
Start-up Times for the Low Frequency Crystal Oscillator Clock Selection
Start-up Time from
Start-up Time from Power-
Start-up Time from
Power-down and
Power-down and
down and Power-save
Reserved
Reserved
Power-save
Power-save
16K CK
16K CK
16K CK
32K CK
32K CK
32K CK
1K CK
1K CK
1K CK
1K CK
Reserved
6 CK
6 CK
6 CK
Additional Delay
Additional Delay
14CK + 4.1 ms
14CK + 65 ms
14CK + 65 ms
14CK + 4.1 ms
14CK + 4.1 ms
14CK + 65 ms
14CK + 65 ms
(V
(V
from Reset
from Reset
CC
CC
14CK
14CK
14CK
Additional Delay from
= 5.0V)
= 5.0V)
Reset (V
14CK + 65 ms
(1)
14CK + 4.1 ms
(2)
(1)
(1)
14CK
ATmega16/32U4
CC
= 5.0V)
CKSEL0
CKSEL0
(1)
1
1
1
1
0
0
0
0
1
1
1
1
Figure
SUT1..0
SUT1..0
SUT1..0
6-2. When this
00
01
10
11
00
01
10
11
00
01
10
11
00
01
10
11
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