Thanks for your comments. POL is grounded, and serial bits are sent low to light a segment. Using analogWrite(blankPin, 200); to enable PWM, most or all segments of all Nixies will light. I think sending alternate serial packets will suck too much CPU.
I grounded POL following the Nixiechron schematic. Somehow dimming works well with that clock. Hopefully the answer is not to connect POL to VCC. Traces are under the PLCC socket. I don't understand the part about inverting CLK. All of this came from a pile of Nixie clock schematics. That is beyond the limit of my knowledge. On Wednesday, June 10, 2015 at 7:33:07 PM UTC-4, gregebert wrote: > > Nice board. > > I'm curious why the blanking pin on the HV5530 isn't working. Is it that > you dont see any dimming, or is it something else ? Be careful about the > setting of the POL pin; if it's at the wrong level you will turn on all > cathodes when you attempt to blank the displays. > > I'm working on a 14-tube IN-18 clock that uses the HV5530, and I plan to > use the blanking pin for dimming. My control logic is entirely FPGA, so I > have no issues about software timing, etc. > > Although it's inefficient, you could implement a lower-speed PWM by > sending alternate serial packets with all cathodes off, then the desired > cathodes on, etc. I dont know if your CPU can handle that workload under > software control, though. > > The datasheet parameters dont specify a *minimum* propagation delay on > the DataOut pin (tDLH), and there is a minimum hold-time requirement on the > DataIn pin, so it's theoretically not possible to cascade these devices > unless you alternately invert the CLK signal or add delay on the DataIn > pin. This wont cause a problem with blanking, but it could cause marginal > operation. I chose to alternately invert the CLK signal. > -- 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/cf7dcb94-14ec-40d1-86a3-d20c83323ebc%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
