ATMEGA328P-15AZ【PDF 67/83 页】MCU AVR 32K FLASH 15MHZ 32-TQFP

收藏本站

您好，
买卖IC网欢迎您。
请登录
免费注册

买卖IC网

Sheet目录1905

63页 64页 65页 66页 [67页]68页 69页 70页 71页

7810C–AVR–10/12

Atmel ATmega328P [Preliminary]

Notes:

1. These options should only be used when not operating close to the maximum frequency of the

device, and only if frequency stability at start-up is not important for the application. These

options are not suitable for crystals.

2. These options are intended for use with ceramic resonators and will ensure frequency stability

at start-up. They can also be used with crystals when not operating close to the maximum fre-

quency of the device, and if frequency stability at start-up is not important for the application.

8.4

Full Swing Crystal Oscillator

Pins XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier which can be

configured for use as an On-chip Oscillator, as shown in Figure 8-2 on page 28. Either a quartz

crystal or a ceramic resonator may be used.

This Crystal Oscillator is a full swing oscillator, with rail-to-rail swing on the XTAL2 output. This is

useful for driving other clock inputs and in noisy environments. The current consumption is

higher than the “Low Power Crystal Oscillator” on page 27. Note that the Full Swing Crystal

Oscillator will only operate for V

CC = 2.7 - 5.5 volts.

C1 and C2 should always be equal for both crystals and resonators. The optimal value of the

capacitors depends on the crystal or resonator in use, the amount of stray capacitance, and the

electromagnetic noise of the environment. Some initial guidelines for choosing capacitors for

use with crystals are given in Table 8-6 on page 30. For ceramic resonators, the capacitor val-

ues given by the manufacturer should be used.

The operating mode is selected by the fuses CKSEL3..1 as shown in Table 8-5.

Notes:

1. The frequency ranges are preliminary values. Actual values are TBD.

2. If 8 MHz frequency exceeds the specification of the device (depends on V

CC), the CKDIV8

Fuse can be programmed in order to divide the internal frequency by 8. It must be ensured

that the resulting divided clock meets the frequency specification of the device.

Crystal Oscillator, BOD

enabled

16K CK

14CK

Crystal Oscillator, fast

rising power

16K CK

14CK + 4.1 ms

Crystal Oscillator, slowly

rising power

16K CK

14CK + 65 ms

Table 8-4.

Start-up Times for the Low Power Crystal Oscillator Clock Selection (Continued)

Oscillator Source /

Power Conditions

Start-up Time from

Power-down and

Power-save

Additional Delay

from Reset

(VCC = 5.0V)

CKSEL0

SUT1..0

Table 8-5.

Full Swing Crystal Oscillator operating modes

(2)

Frequency Range(1)

(MHz)

Recommended Range for

Capacitors C1 and C2 (pF)

CKSEL3..1

0.4 - 16

12 - 22

011

发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

*型号	*数量	厂商	批号	封装

添加更多采购

采购需求

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

我的联系方式