The flash is the charge coupled from the fast rising transistor drains coupled into the gates that turns on all segments just before the processor boots and sets all segments to off. This is the result of avoiding putting pull down resistors on every gate for space considerations.
The first thing to check is whether you are getting an ACK from the first address write to the device, 0x10 for write and 0x11 for read: Note that 0x10/0x11 is the full 8 bit address of the device with the Read/nWrite bit included and not a 7 bit address that needs to be shifted left to be 0x20 and 0x21 for write and read respectively. This can be clearly seen in figures 16a and 16b of the datasheet (http://www.tayloredge.com/storefront/SmartNixie/DataSheets/Datasheet_SmartNixie.pdf). If you are getting the ACK then the addressing is correct and then you can move on to register access problems. jt On Tuesday, August 25, 2015 at 10:47:57 AM UTC-7, TheJBW wrote: > > John, > > Thanks for the advice. I definitely had the polarity of the switches wrong > in my head. Unfortunately, I am still getting no joy out of the tubes. > After a long power off, they will flash briefly when brought up, so I am > fairly confident that the micro is alive. Voltages look good, and I am > seeing clean pulses on the i2c lines... I tried poking the brightness > register as in the datasheet, just in case, as well. > -- 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 [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/c18d6669-bcc2-4197-92c3-76ae7af55c3f%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
