ATMEGA32U4-AU Atmel, ATMEGA32U4-AU Datasheet - Page 32

• Manufacturer Part Number: ATMEGA32U4-AU
• Description: MCU AVR 32K FLASH 16MHZ 44-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA32U4-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 26
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2.5K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Processor Series: ATMEGA32x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2.5 KB
• Interface Type: SPI/TWI/USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 26
• Number Of Timers: 5
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12-ch x 10-bit
• Cpu Family: ATmega
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 16MHz
• Total Internal Ram Size: 2.5KB
• # I/os (max): 26
• Number Of Timers - General Purpose: 5
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 44
• Package Type: TQFP
• Controller Family/series: AVR MEGA
• No. Of I/o's: 26
• Eeprom Memory Size: 1KB
• Ram Memory Size: 2.5KB
• Cpu Speed: 16MHz
• Rohs Compliant: Yes
• For Use With: ATSTK524 - KIT STARTER ATMEGA32M1/MEGA32C1ATSTK600 - DEV KIT FOR AVR/AVR32ATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATMEGA32U4-16AU; ATMEGA32U4-16AU

6.5
6.5.1
7766F–AVR–11/10
Calibrated Internal RC Oscillator
Oscillator Calibration Register – OSCCAL
Note:
The calibrated internal RC Oscillator by default provides a 8.0 MHz clock. This frequency is
nominal value at 3V and 25°C. The device is shipped with the CKDIV8 Fuse programmed. See
“System Clock Prescaler” on page 37
clock by programming the CKSEL Fuses as shown in
no external components. During reset, hardware loads the calibration byte into the OSCCAL
Register and thereby automatically calibrates the RC Oscillator. At 3V and 25°C, this calibration
gives a frequency of 8 MHz ± 1%. The oscillator can be calibrated to any frequency in the range
7.3 - 8.1 MHz within ±1% accuracy, by changing the OSCCAL register. 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 calibration value, see the sec-
tion
Table 6-7.
Notes:
When this Oscillator is selected, start-up times are determined by the SUT Fuses as shown in
Table 6-5 on page
Table 6-8.
• Bits 7..0 – CAL7..0: Oscillator Calibration Value
The Oscillator Calibration Register is used to trim the Calibrated Internal RC Oscillator to
remove process variations from the oscillator frequency. The factory-calibrated value is automat-
ically written to this register during chip reset, giving an oscillator frequency of 8.0 MHz at 25°C.
The application software can write this register to change the oscillator frequency. The calibra-
tion range is +/- 40% and linear (calibration step ~0.4%). With typical process at 25°C the code
should be 127 for 8 MHz. Input value of 0x00 gives the lowest frequency, and 0xFF the highest.
Bit
Read/Write
Initial Value
Power Conditions
BOD enabled
Fast rising power
Slowly rising power
“Calibration Byte” on page 349
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. The frequency ranges are preliminary values. Actual values are TBD.
3. If 8 MHz frequency exceeds the specification of the device (depends on V
application.
Fuse can be programmed in order to divide the internal frequency by 8.
7
CAL7
R/W
Device Specific Calibration Value
Frequency Range
Internal Calibrated RC Oscillator Operating Modes
Start-up times for the internal calibrated RC Oscillator clock selection
31.
6
CAL6
R/W
7.3 - 8.1
Start-up Time from Power-
down and Power-save
5
CAL5
R/W
(2)
(MHz)
Reserved
6 CK
6 CK
6 CK
for more details. This clock may be selected as the system
4
CAL4
R/W
3
CAL3
R/W
2
CAL2
R/W
Table
Additional Delay from
Reset (V
14CK + 4.1 ms
14CK + 65 ms
6-7. If selected, it will operate with
14CK
1
CAL1
R/W
ATmega16/32U4
CC
(1)(3)
CKSEL[3:0]
= 5.0V)
0010
0
CAL0
R/W
CC
SUT1..0
OSCCAL
), the CKDIV8
00
01
10
11
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