<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Vadi, ona je ta ctvrta radove drazsi.<br />
2.Souhlas, otazkou je zda je lze nahradit necim jako je 74HC241, ten by snad mel mit ochrane diody na vstupech i vystupech nebo se pletu, hledal jsme u Philipsu, ale v DS to nepisi a dalsi dokumenty se mi nejak nepodarilo najit.<br />
<br />
Pavel<br />
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>1. Je otazka, jestli vubec vadi, ze v pripade tri vadnych soucastek odejde jeste ctvrta ... spise bych resil nasledky - co se stane v pripade poruchy MCU, aby skody nebyly moc velke.</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">2. Podle meho vetsi problemy nez prima destrukce muze u techto zapojeni zpusobit nizka odolnost MCU proti ruznym rusivym impulzum, kterych na techto vyssich napetovych hladinach muze byt dost, vlivem parazitnich kapacit "prolezou" vsim a mohou narusit funkci programu. Pak muze byt pouziti ochrannych diod nezbytnosti</font></font></p>
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<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font face="Calibri" size="3">Martin. </font><a href="mailto:persich@transcon.cz"><font face="Calibri" size="3" color="#0000ff">persich@transcon.cz</font></a></p>
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<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">----- Original Message -----</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">From: "Pavel Dolnsky" <p.dolnsky@atlas.cz></font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">To: <hw-list@list.hw.cz></font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Sent: Monday, September 13, 2010 10:59 AM</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Subject: "Ochrana" I/O MCU?</font></font></p>
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<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font face="Calibri" size="3"> </font></p>
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<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Mam desku na ktere jsou i napeti jako 100V a podobne,do ni se ma zasouvat</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">dalsi deska s ridicim MCU.</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">MCU by teoreticky nikdy nemel prijit do styku s timto napetim.</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">V nejhorsim pripade by musel odejit 2x T a jeden odpor cca 4k, pak se toto</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">napeti dostane na odporovy delic na jehoz stredu se pak muze objevit 20V</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">1mA. Stred je blokovan BAV99 diodou.</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Ostatni I/O pres T spinaji relatka nebo analogove spinace typu DG4xx.</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Prijde mi tak trochu vosaistlich, jelikoz tyto nejsou nijak extra interne</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">blokovany a nezvladaji vice nez 1mA.</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Osazoval na kazdy I/O chrane diody typu BAV99 se mi moc nechce.</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Napadlo me pouzit neco jako 74HC541 a spolehnout se na to, ze 74HC maji</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">nejakou interni ochramu a kdyz by odeslo vsechno tak snad shori jen ta 74HC.</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Je to nesmysl?</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Jak to resite?</font></font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font face="Calibri" size="3"> </font></p>
<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Dekuji</font></font></p>
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<p class="MsoPlainText" style="margin: 0cm 0cm 0pt;"><font size="3"><font face="Calibri">Pavel</font></font></p>