All Forums  MCUmall Forums  True USB Willem Programmer (GQ-2X,3X,4X & GQ-4x4)  GQ-4X and problems with Dallas DS1250Y NVRAM

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Screensize: 640 x 480 800 x 600 1024 x 768 1280 x 1024 UserName: Password: Format Mode: Basic  Help  Prompt  Format: Font Andale Mono Arial Arial Black Book Antiqua Century Gothic Comic Sans MS Courier New Georgia Impact Lucida Console Script MT Bold Stencil Tahoma Times New Roman Trebuchet MS Verdana   Size 1 2 3 4 5 6   Color Black Red Yellow Pink Green Orange Purple Blue Beige Brown Teal Navy Maroon LimeGreen Message: * HTML is OFF * Forum Code is ON Smilies [quote][i]Originally posted by rochoz[/i] [br]Hi all, I am having problems when continually verifying Dallas DS1250Y NVRAM modules using the GQ-4X. The problem is if I continually verify one of these DS1250Y devices, usually after 3 or 4 verifies eventually some random location no longer verifies. The byte that gets corrupted stays corrupted, until you verify enough times that a different location gets clobbered. I initially suspected a bad DS1250 part, but I have been able to recreate this problem on 4 different devices, 2 of which are brand new. I do not have this problem if I bring any of these devices to work and verify them on an expensive DataIO programmer. I suspect the GQ4X is doing something at power off. I connected my digital scope and found that there are numerous glitches on the WE signal during power down, as well as undershoot of around 900mV, at around when VCC is 3V. Neither of these are a desirable feature. In fact, the datasheet has a very bold warning that absolutely no undershoot is allowed when the part is in battery backup mode (ie, when VCC is less than 4.5V). Is this a known problem? Can it be fixed? Thanks, Mike [/quote]    Insert an Image File Check here to include your profile signature.