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參數(shù)資料
| 型號(hào)： | X4283 |
| 元件分類： | CPU監(jiān)測(cè) |
| 英文描述： | RTC Module With CPU Supervisor |
| 中文描述： | 時(shí)鐘模塊CPU監(jiān)控 |
| 文件頁(yè)數(shù)： | 1/2頁(yè) |
| 文件大小： | 24K |
| 代理商： | X4283 |
Application Note
AN109
AN109-1
Adding a Manual Reset to Xicor CPU Supervisors
by Applications Staff, September 1998
Introduction
The Xicor CPU Supervisors provides a number of impor-
tant system monitoring and reset functions that help
insure high system reliability (See Application Note
AN108.) However, there are times when it is desired to
also include a manual reset switch. This application note
explores several different approaches.
Force the Reset
The first, simplest, solution is to add a “debounced switch
to the RESET signal (see Figure 1.) In this circuit, the
open drain RESET output of the Supervisory EEPROM is
pulled HIGH to give the normal, inactive reset signal to the
microcontroller. The manual reset switch pulls down the
RESET signal, with the capacitor providing some
debounce.
Figure 1. Reset Switch (Active LOW Reset)
The main disadvantage to this circuit is that the length of
the pulse is indeterminate, which might result in some
problems with some controllers. A second problem with
this solution is that it doesn’t work well with an active HIGH
reset signal. In this case (see Figure 2.), the RESET out-
put is pulled up, but is normally LOW. Adding a switch to
pull RESET HIGH results in contention in the output driver.
It will work, but can put strain on the output buffer.
Figure 2. Reset Switch (Active HIGH Reset)
Use Low Voltage Reset
A mechanism that works for both active HIGH and active
LOW reset makes use of the Xicor CPU supervisor low
voltage sense circuit. In this case, a switch and three
diodes are added to the Vcc line of the supervisor (see
Figure 3.) Opening the switch drops the power to the CPU
supervisor only, from above 4.55V to below 4.25 volts. As
power to the Vcc line drops below the trip point, the reset
pin goes active, resetting the system. The supervisor then
provides a clean reset signal and doesn’t release the reset
signal for 250ms (nominal) after the Vcc supply returns.
The reset output is pulled up to 5V providing either an
active HIGH or active LOW reset.
CS
SI
SO
SCK
Micro
Controller
Supervisory
EEPROM
RESET
RST
Vcc
CS
SI
SO
SCK
Micro
Controller
Supervisory
EEPROM
RESET
RST
Vcc
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| X4323 | RTC Module With CPU Supervisor |
| X4325 | RTC Module With CPU Supervisor |
| X4643(中文) | RTC Module With CPU Supervisor |
| X4645(中文) | RTC Module With CPU Supervisor |
| X4C105 | RTC Module With CPU Supervisor |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| X4283_06 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:CPU Supervisor with 128K EEPROM |
| X4283AL | 制造商:XICOR 制造商全稱:Xicor Inc. 功能描述:CPU Supervisor with 128K EEPROM |
| X4283AM | 制造商:XICOR 制造商全稱:Xicor Inc. 功能描述:CPU Supervisor with 128K EEPROM |
| X4283AN | 制造商:XICOR 制造商全稱:Xicor Inc. 功能描述:CPU Supervisor with 128K EEPROM |
| X4283AP | 制造商:XICOR 制造商全稱:Xicor Inc. 功能描述:CPU Supervisor with 128K EEPROM |
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