I have written previously about a similar incident with ATmega328p chips ordered from Aliexpress. They did not arrived in a reel, but just packed in a small plastic bag. Two of them worked fine, but Atmel Studio was unable to even read the ID of the third one, thus rendering it unprogrammable and useless..and since it's an SMD, it was not as easy as just popping it out of the socket. I guess they are chips which failed QC and somehow, these companies got them, performed a somewhat "basic check" and sold them as new ones.
I have also ordered a lot of 10 DS3231 chips from some other Aliexpress seller (they had considerable 5* ratings so I decided to give it a try). They were like 14$/10pcs. The chips worked, the time is still very precise after two years of operation of the older clock I made. However, I did notice one "bug" in the chip. If you keep querying the chip too often (like in an unconditional loop) for seconds, it will eventually hang the I2C line. The solution was to set a timeout for I2C read operation, and if timeout does occur, the master (microcontroller) has to keep clocking the SCL line until the DS3231 releases the bus. However, I've read some people reporting the same "bug" on multiple sites, so I'm not sure if it's a "bug" specific to possibly counterfeit chips or just a general bug that affects genuine ones as well. On Thursday, January 3, 2019 at 1:41:52 AM UTC+1, gregebert wrote: > > For now I'm going to hold off on any experiments that require > code-changes. I'll keep this RTC chip online for additional experiments; > known-good RTC will go into the second board-set. > It appears the alarm registers are testable with software; I dont have the > INT/SQW pin connected in my system. > > I'm really itching to get the NIMO lit-up and running. So close to > actually firing it up, but I wont attempt that unless everything is 100% > stable. Mindset is that I have only 1 chance to get it right and it must be > right the first time. Anything that can go wrong and remain uncorrected for > more than a few milliseconds is assumed to result in a dead NIMO tube, and > I only have 1. > > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/9529a437-2084-41b9-af82-158aa95ff505%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
