A000046 Arduino, A000046 Datasheet - Page 34

• Manufacturer Part Number: A000046
• Description: MCU, MPU & DSP Development Tools Uno
• Manufacturer: Arduino
• Series: -r
• Type: MCUr

Specifications of A000046

• Processor To Be Evaluated: ATmega328
• Interface Type: USB, I2C, SPI
• Dimensions: 2.7 in x 2.1 in
• Operating Supply Voltage: 5 V
• Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: ATmega328

8.7
8.8
8161D–AVR–10/09
128 kHz Internal Oscillator
External Clock
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 8-13.
Note:
When this clock source is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 8-14.
Note:
To drive the device from an external clock source, XTAL1 should be driven as shown in
8-4 on page
to “0000” (see
Table 8-15.
Figure 8-4.
When this clock source is selected, start-up times are determined by the SUT Fuses as shown in
Table
BOD enabled
Fast rising power
Slowly rising power
Power Conditions
8-14.
8-16.
1. Note that the 128 kHz oscillator is a very low power clock source, and is not designed for high
1. If the RSTDISBL fuse is programmed, this start-up time will be increased to
accuracy.
14CK + 4.1 ms to ensure programming mode can be entered.
34. To run the device on an external clock, the CKSEL Fuses must be programmed
128 kHz Internal Oscillator Operating Modes
Start-up Times for the 128 kHz Internal Oscillator
Table
Crystal Oscillator Clock Frequency
External Clock Drive Configuration
Nominal Frequency
8-15).
Frequency
0 - 20 MHz
EXTERNAL
128 kHz
SIGNAL
CLOCK
Start-up Time from Power-
down and Power-save
NC
ATmega48PA/88PA/168PA/328P
(1)
Reserved
6 CK
6 CK
6 CK
Table
XTAL2
XTAL1
GND
8-13.
Additional Delay from
14CK + 64 ms
14CK + 4 ms
14CK
Reset
CKSEL3..0
CKSEL3..0
(1)
0011
0000
SUT1..0
Figure
00
01
10
11
34