Citlivost pouzdra SDRAM na statickou el. ???

[Jaroslav Buchta]

To asi ne, jednak je to prezvaty kod z projektu atmelu, kde jsou jen 
upraveny Row a Columns pocty adres, refresh je po 7uS coz je pro tu 
pamet 4Mx32 az dost...  A hlavne testovaci program je jednoducha smycka 
co blika diodama a probehne hodnekrat za sec. takze by se to 
refreshovalo snad i samo.
Prekvapuje me, ze vadi sahnuti na pouzdro bez dotyku cehokoli vodiveho...
Jinak program bezi uz 10h bez problemu v SDRAM.
Dne 29.9.2012 12:25, Slavomir Skopalik napsal(a):
> A neni problem s refresh?
>
> Auto refresh
>
> It is possible to refresh a RAM chip by opening and closing (activating and
> precharging) each row in each bank. However, to simplify the memory
> controller, SDRAM chips support an "auto refresh" command, which performs
> these operations to one row in each bank simultaneously. The SDRAM also
> maintains an internal counter, which iterates over all possible rows. The
> memory controller must simply issue a sufficient number of auto refresh
> commands (one per row, 4096 in the example we have been using) every refresh
> interval (tREF = 64 ms is a common value). All banks must be idle (closed,
> precharged) when this command is issued.
>
> Slavek
>
> Ing. Slavomir Skopalik
> Jednatel spolecnosti
> Elekt Labs s.r.o.
> Sber a vyhodnoceni dat ze stroju a laboratori
> systemem MASA (http://www.elektlabs.cz/m2demo)
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>
>> -----Original Message-----
>> From: hw-list-bounces na list.hw.cz
>> [mailto:hw-list-bounces na list.hw.cz] On Behalf Of Jaroslav Buchta
>> Sent: Saturday, September 29, 2012 10:17 AM
>> To: HW-news
>> Subject: Fwd: Citlivost pouzdra SDRAM na statickou el. ???
>>
>>
>> Tak pri hrani s ARMem jsem narazil na dalsi zahadu, kdyz
>> polozim prst na
>> pouzdro SDRAM tak se spolehlive poskodi obsah, program se zabehne -
>> myslim na pouzdro, bez dotyku vodivych casti. Pokud se druhou rukou
>> drzim zeme, tak je to podstatne min pravdepodobne a pokud
>> saham na ruzne
>> vodive cesty - data, adresy i SCLK tak to vubec nevadi. Muze
>> to byt tim,
>> ze se prenese naboj do kondenzatoru na cipu nebo je nekde
>> nejaka chyba?
>> Jinak program beze pul dne bez nehody, na frekvenci hodin
>> nejak zda se
>> nezalezi. Deska je 4-vrstva a napajeni SDRAM je bohate blokovano
>>
>>
>>
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