3 ms·
Except most cars don't rewrite their flash every few seconds. Most modules with flash in 'em are programmed once at the manufacturer, reflashed once or twice d
by myself248 7y ago
Except most cars don't rewrite their flash every few seconds.
Most modules with flash in 'em are programmed once at the manufacturer, reflashed once or twice during assembly, maybe reflashed once more at the dealer before delivery, and that's it. Maybe again post-sale if there's a recall or TSB or something that can be fixed in software.
Flash quite happily lasts 25+ years if you don't abuse it far beyond any flash manufacturer's wearout specs. Go figure!
- t34543 7y agoAirbag control modules do constantly write data. The last 5 seconds or so of sensor and input data is recorded for crash investigations.
- cat199 7y agois this actually written to flash? concievably a big capacitor or watch battery could keep a 4 or 8k RAM going for quite a long time.
- beerandt 7y agoIt's got to survive a wreck, so I suspect power reliant memory is out.
- xfitm3 7y agoIf you look at airbag module teardowns there is a giant capacitor, but this is used to fire airbags in the event the vehicle's power system is rendered inoperable prior to deployment.
- leoedin 7y agoFlash isn't the only game in town. I wouldn't be surprised if airbags use FRAM - capable of more than 1 trillion write cycles
- cat199 7y agothanks - learning things :)
- dfox 7y agoMost manufacturers’ datasheets specify 20 or less years of data retention (even when powered on). This might seem like random sufficiently large number, but there really are devices made in mid-90’s (notably early FastEthernet cards) that do not work because they lost contents of their configuration EEPROMs.