ATMEGA32A-MNR Atmel, ATMEGA32A-MNR Datasheet - Page 30

• Manufacturer Part Number: ATMEGA32A-MNR
• Description: IC MCU AVR 32K 16MHZ 44VQFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA32A-MNR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• 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: 44-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.7
8.8
8155C–AVR–02/11
Calibrated Internal RC Oscillator
External Clock
The Calibrated Internal RC Oscillator provides a fixed 1.0, 2.0, 4.0, or 8.0 MHz clock. All fre-
quencies are nominal values at 5V and 25°C. This clock may be selected as the system clock by
programming the CKSEL fuses as shown in
components. The CKOPT Fuse should always be unprogrammed when using this clock option.
During Reset, hardware loads the calibration byte for the 1MHz into the OSCCAL Register and
thereby automatically calibrates the RC Oscillator. At 5V, 25°C and 1.0MHz Oscillator frequency
selected, this calibration gives a frequency within ±3% of the nominal frequency. Using calibra-
tion methods as described in application notes available at www.atmel.com/avr it is possible to
achieve ±1% accuracy at any given V
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 section
bration Byte” on page
Table 8-8.
Note:
When this Oscillator is selected, start-up times are determined by the SUT fuses as shown in
Table
Table 8-9.
Note:
To drive the device from an external clock source, XTAL1 should be driven as shown in
8-4 on page
to “0000”. By programming the CKOPT Fuse, the user can enable an internal 36pF capacitor
between XTAL1 and GND.
SUT1:0
10
00
01
11
8-9. XTAL1 and XTAL2 should be left unconnected (NC).
(1)
1. The device is shipped with this option selected.
1. The device is shipped with this option selected.
31. To run the device on an external clock, the CKSEL fuses must be programmed
Internal Calibrated RC Oscillator Operating Modes
Start-up Times for the Internal Calibrated RC Oscillator Clock Selection
Start-up Time from
Power-down and
CKSEL3:0
0001
Power-save
0010
0011
0100
269.
6 CK
6 CK
6 CK
(1)
CC
and Temperature. When this Oscillator is used as the
Table
Additional Delay
(V
from Reset
CC
4.1ms
Reserved
8-8. If selected, it will operate with no external
65ms
= 5.0V)
–
Nominal Frequency (MHz)
Recommended Usage
BOD enabled
Fast rising power
Slowly rising power
1.0
2.0
4.0
8.0
ATmega32A
Figure
“Cali-
30