Hi Spencer, thank you for your replay. Since the RTC is made with an smd component, I was not able to solder the capacitor directly to the pin of the ds1307. But i solderd it quite near to the power pin. It seems to be a little bit better but still has the error.
With the oscilloscope, when I look at the SCL, I see a 100kHz square wave. the rise is about 700 ns. When I increase the voltage on the DC/DC step up circuit, all of a sudden i see instead the SCL square wave just a flat line at 5 Volt level. <https://lh3.googleusercontent.com/-dsAN2UCKHr4/UZFZgstjWyI/AAAAAAAABIg/-DpF4IPJk_w/s1600/2.jpg><https://lh4.googleusercontent.com/-TaCTm0U_lx0/UZFZa8r7dlI/AAAAAAAABIY/bjrZc9FPxAo/s1600/1.jpg> The high voltage from the DC/DC step up converter showes at the upper end where the issue exist bigger ripples. Sergio Am Montag, 13. Mai 2013 16:17:26 UTC+2 schrieb Spencer: > > You want a small capacitor, usually 0.1uF on each power supply of the ic > as close as possible to the pins. > > So on the ds1307, you want it on pin 8 as close as possible. > > This image shows what I mean, [image: ds1307exampleuse.jpg] > > This goes a little deeper into why its needed, > http://hackaday.com/2008/09/29/parts-01uf-decoupling-capacitors/ > > Sent from my iPhone > > On May 13, 2013, at 6:49 AM, nix <[email protected] <javascript:>> > wrote: > > not sure. There is a capacitor on the highvoltage power supply. is this a > decoupling capacitor? > > Am Montag, 13. Mai 2013 13:45:46 UTC+2 schrieb Spencer: >> >> Do you have decoupling capacitors on all ic's? >> >> Sent from my iPhone >> >> On May 13, 2013, at 6:19 AM, nix <[email protected]> wrote: >> >> Hello I just build my own Nixie clock with input from Arduinix.com and a >> power supply from ledsale (Build a nixie power supply - >> LEDsales<http://www.google.ch/url?sa=t&rct=j&q=nixie%20power%20supply&source=web&cd=5&cad=rja&ved=0CEEQFjAE&url=http%3A%2F%2Fwww.ledsales.com.au%2Fkits%2Fnixie_supply.pdf&ei=-smQUbLsKvD24QSX9IDgDA&usg=AFQjCNEiqKM6Acf_mlaSDuBrhUqL2A5Uvw&sig2=Bi2PdGfH0ERKhqQkk5wFQA&bvm=bv.46340616,d.bGE> >> ) >> >> Attached find the circuit and the pcb from fritzing. The clock works fine >> but when I adjust the high voltage with R36 the ds1307 module from Twig >> http://shop.boxtec.ch/twig-ds1307-p-40355.html starts to flicker because >> on the serial interface it shows strange numbers like *165*:*165*:85. >> After a while it does not return the time over the i2c interface at all. A >> restart of the nixie clock starts showing the time again. With an >> oscilloscope I can see that after a certain position on R36 the SDA puls >> disapear and it shows a flat line. I think it is at high level. Not so >> shure how to read the oscilloscope. >> >> Any Idea why? I don't see a direct link from the high voltage power >> supply to the 2 wire interface. (see attached circuit) >> >> Kind regards >> >> Sergio >> >> -- >> 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/msg/neonixie-l/-/jgtKRhvfY7IJ. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> >> -- > 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] <javascript:>. > To post to this group, send an email to [email protected]<javascript:> > . > To view this discussion on the web, visit > https://groups.google.com/d/msg/neonixie-l/-/TaAzQP23KfEJ. > For more options, visit https://groups.google.com/groups/opt_out. > > > > -- 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/msg/neonixie-l/-/_2aa1Yv6hRsJ. For more options, visit https://groups.google.com/groups/opt_out.
