ATMEGA168V-10MI【PDF 17/36 页】IC AVR MCU 16K 10MHZ 32-QFN

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3834

13页 14页 15页 16页 [17页]18页 19页 20页 21页

2545TS–AVR–05/11

ATmega48/88/168

11.1.4

Rev A

Part may hang in reset

Wrong values read after erase only operation

Watchdog timer interrupt disabled

Start-up time with crystal oscillator is higher than expected

High power consumption in power-down with external clock

Asynchronous oscillator does not stop in power-down

Interrupts may be lost when writing the timer registers in the asynchronous timer

Part may hang in reset

Some parts may get stuck in a reset state when a reset signal is applied when the internal

reset state-machine is in a specific state. The internal reset state-machine is in this state for

approximately 10ns immediately before the part wakes up after a reset, and in a 10ns win-

dow when altering the system clock prescaler. The problem is most often seen during In-

System Programming of the device. There are theoretical possibilities of this happening also

in run-mode. The following three cases can trigger the device to get stuck in a reset-state:

- Two succeeding resets are applied where the second reset occurs in the 10ns window

before the device is out of the reset-state caused by the first reset.

- A reset is applied in a 10ns window while the system clock prescaler value is updated by

software.

- Leaving SPI-programming mode generates an internal reset signal that can trigger this

case.

The two first cases can occur during normal operating mode, while the last case occurs only

during programming of the device.

Problem fix/workaround

The first case can be avoided during run-mode by ensuring that only one reset source is

active. If an external reset push button is used, the reset start-up time should be selected

such that the reset line is fully debounced during the start-up time.

The second case can be avoided by not using the system clock prescaler.

The third case occurs during In-System programming only. It is most frequently seen when

using the internal RC at maximum frequency.

If the device gets stuck in the reset-state, turn power off, then on again to get the device out

of this state.

Wrong values read after erase only operation

At supply voltages below 2.7V, an EEPROM location that is erased by the Erase Only oper-

ation may read as programmed (0x00).

Problem fix/workaround

If it is necessary to read an EEPROM location after Erase Only, use an Atomic Write opera-

tion with 0xFF as data in order to erase a location. In any case, the Write Only operation can

be used as intended. Thus no special considerations are needed as long as the erased loca-

tion is not read before it is programmed.

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