ATMEGA2561R231-MU Atmel, ATMEGA2561R231-MU Datasheet - Page 47

• Manufacturer Part Number: ATMEGA2561R231-MU
• Description: BUNDLE ATMEGA2561/RF231 QFN
• Manufacturer: Atmel

Specifications of ATMEGA2561R231-MU

• Frequency: 2.4GHz
• Modulation Or Protocol: 802.15.4 Zigbee, 6LoWPAN, RF4CE, SP100, WirelessHART™, ISM
• Data Interface: PCB, Surface Mount
• Memory Size: 256kB Flash, 4kB EEPROM, 8kB RAM
• Antenna Connector: PCB, Surface Mount
• Package / Case: 64-QFN, 32-QFN
• Processor Series: ATMEGA256x
• Core: AVR8
• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 256 KB
• Data Ram Size: 8 KB
• Development Tools By Supplier: ATAVRRZ541, ATAVRRAVEN, ATAVRRZUSBSTICK, ATAVRISP2, ATAVRRZ201
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Supply: -
• Power - Output: -
• Operating Temperature: -
• Applications: -
• Sensitivity: -
• Data Rate - Maximum: -
• Current - Transmitting: -
• Current - Receiving: -
• Lead Free Status / Rohs Status: Details

9.8
2549M–AVR–09/10
128 kHz Internal Oscillator
This clock may be selected as the system clock by programming the CKSEL Fuses as shown in
Table
the pre-programmed calibration value into the OSCCAL Register and thereby automatically cal-
ibrates the RC Oscillator. The accuracy of this calibration is shown as Factory calibration in
Table 30-1 on page
By changing the OSCCAL register from SW, see
page
The accuracy of this calibration is shown as User calibration in
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 cali-
bration value, see the section
Table 9-9.
Notes:
When this Oscillator is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 9-10.
Note:
The 128 kHz internal Oscillator is a low power Oscillator providing a clock of 128 kHz. The fre-
quency is nominal at 3V and 25°C. This clock may be select as the system clock by
programming the CKSEL Fuses to “11” as shown in
Table 9-11.
Note:
Slowly rising power
Power Conditions
Fast rising power
50, it is possible to get a higher calibration accuracy than by using the factory calibration.
9-9. If selected, it will operate with no external components. During reset, hardware loads
9-10.
BOD enabled
1. The device is shipped with this option selected.
2. If 8 MHz frequency exceeds the specification of the device (depends on V
1. The device is shipped with this option selected.
1. Note that the 128 kHz oscillator is a very low power clock source, and is not designed for high
Fuse can be programmed in order to divide the internal frequency by 8.
accuracy.
Internal Calibrated RC Oscillator Operating Modes
Start-up times for the internal calibrated RC Oscillator clock selection
128 kHz Internal Oscillator Operating Modes
Frequency Range (MHz)
Nominal Frequency
371.
7.3 - 8.1
128 kHz
Start-up Time from Power-
“Calibration Byte” on page
down and Power-save
ATmega640/1280/1281/2560/2561
Reserved
6 CK
6 CK
6 CK
“OSCCAL – Oscillator Calibration Register” on
Table
338.
9-11.
(1)
Additional Delay from
Table 30-1 on page
Reset (V
14CK + 65 ms
14CK + 4.1 ms
(1)(2)
14CK
CC
CKSEL3:0
CKSEL3:0
= 5.0V)
0010
0011
(1)
CC
), the CKDIV8
371.
SUT1:0
00
01
10
11
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