ATMEGA3290P datasheet(32/360 Pages) ATMEL

32 / 360 page

8021A–AVR–12/06

ATmega329P/3290P

Figure 7-3.

Crystal Oscillator Connections

Table 7-6.

Low-frequency Crystal Oscillator Internal load Capacitance

Crystals specifying load capacitance (CL) higher than 6 pF, require external capacitors applied

as described in Figure 7-2 on page 30.

To find suitable load capacitance for a 32.768 kHz crystal, please consult the crystal datasheet.

The Low-frequency Crystal Oscillator must be selected by setting the CKSEL Fuses to “0110” or

“0111” as shown in Table 7-8. Start-up times are determined by the SUT Fuses as shown in

Table 7-7.

Note:

1. This option should only be used if frequency stability at start-up is not important for the

application

7.6

Calibrated Internal RC Oscillator

By default, the Internal RC Oscillator provides an approximate 8 MHz clock. Though voltage and

temperature dependent, this clock can be very accurately calibrated by the user. The device is

shipped with the CKDIV8 Fuse programmed. See ”System Clock Prescaler” on page 35 for

more details.

This clock may be selected as the system clock by programming the CKSEL Fuses as shown in

Table 7-9 on page 33. If selected, it will operate with no external components. During reset,

hardware loads the pre-programmed calibration value into the OSCCAL Register and thereby

Min. (pF)

Typ. (pF)

Max. (pF)

TBD

Table 7-7.

Start-up Times for the Low-frequency Crystal Oscillator Clock Selection

SUT1..0

Additional Delay from Reset (VCC = 5.0V)

Recommended Usage

4 CK

Fast rising power or BOD enabled

4 CK + 4.1 ms

Slowly rising power

4 CK + 65 ms

Stable frequency at start-up

Reserved

Table 7-8.

Start-up Times for the Low-frequency Crystal Oscillator Clock Selection

CKSEL3..0

Start-up Time from

Power-down and Power-save

Recommended Usage

0110(1)

1K CK

0111

32K CK

Stable frequency at start-up

XTAL2 (TOSC2)

XTAL1 (TOSC1)

ATMEGA3290P Datasheet(PDF) 32 Page - ATMEL Corporation

ATMEGA3290P Datasheet(HTML) 32 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL