Hello! It looks like I was in a Mistake with the datasheet of the crystal, thinking that the 6.0 to 12.5 pf capacitors would be perfect for the time running perfect, But with this configuration, I have like 2 mins of delay in 24H.
I really appreciate the help, Just took a quick look and you are right, 22-27Pf and 220K ohm seems that is going to fix the delay I have. I will have a good reading of the links you added, will try, and will let you know. Thanks a lot! El lun, 19 jul 2021 a las 1:24, gregebert (<gregeb...@hotmail.com>) escribió: > It is gaining time, or losing time ? > > If it's losing time, could it be caused by execution delays in your > software ? I've seen some really bizarre things happening with my Raspberry > Pi based clocks because of the chaotic behavior of Linux, and I have even > seen metastability-related failures due to the way I had software scanning > hardware for asynchronous events. They are fixable, but they definitely > challenge your debugging skills. > > BTW, the last time I saw such a thing was *yesterday*....I'm testing my > RZ568m tubes for a new clock, and saw my time jump by 2 seconds, instead of > the usual 1 second, because of the way in which I update the displayed > time. These are often subtle bugs you dont catch while typing-in your code. > > On Sunday, July 18, 2021 at 12:19:21 PM UTC-7 Dekatron42 wrote: > >> The capacitance you cite from the datasheet is not the recommended >> capacitance for the external capacitors, it is the load capacitance of the >> crystal - you must check your ordering document to see which crystal you >> got unless you can read the information on the crystal itself if it is >> laser printed there. The load capacitance can then be used to calculate >> what capacitance value you need for the two other capacitors - do a quick >> test with two 22pF or 27pF capacitors if you have the crystal with CL = >> 12.5pF - twice the load capacitance from the formula in the application >> note: http://ww1.microchip.com/downloads/en/appnotes/91097a.pdf is >> usually a good start, so if you have a lower CL value use twice that for >> tests. >> >> Neither is the series resistance in the datasheet the value you need for >> the external resistor, it is the internal resistance of the crystal itself. >> You should use the value in the application note to start with, 220k - it >> might be that you have damaged the small crystal by over driving it if you >> used a lower value, it is explained in the application note why you need to >> protect the crystal from over driving. You can read some on series >> resistance and crystal selection here: >> https://www.maximintegrated.com/en/design/technical-documents/tutorials/7/726.html >> . The datasheets and product documentation found on the manufacturer >> website: >> https://www.microcrystal.com/en/products/khz-quartz-crystals/ms3v-t1r/ >> and >> https://www.microcrystal.com/en/products/khz-quartz-crystals/ms1v-t1k/ >> do contain the equivalent circuit for the crystal similar to the one above. >> >> So try with twice the load capacitance for both capacitors and use the >> recommended 220k resistor as in the application note and see how it behaves >> - also use the pins recommended in the application note, ie CLKIN & CLKOUT. >> >> /Martin >> On Sunday, 18 July 2021 at 20:53:32 UTC+2 MrThe50sanchez wrote: >> >>> Hello Again group! >>> >>> >>> I've been testing this for a while, and I still have some delay minutes. >>> This is the PCB design I'm using and components. >>> >>> *Components: * >>> ·PIC16F1936 >>> ·CRYSTAL MS3V-T1R CRYSTAL 32.768 Khz. >>> ·Capacitors ( used 6.0 ; 7.0 ; 9.0 & 12.5) pF as datasheet from crystal >>> recommend. >>> ·Resistor value between 50/65 K ohm. >>> >>> *PCB Design: * >>> >>> This design is done following the document you guys added called: >>> Microship TB097 which give's good instructions on how install Crystals to >>> our pics. >>> >>> >>> Guys, My head is gonna explote because I don't find the problem that is >>> making minutes delays in 24H (About 3 mins per 24H). >>> >>> I'm questioning two fact's that can be making this delay: >>> >>> *1.* Pins connections between Crystal + Pic. In some other designs, >>> crystal is attached to other pins. For example. >>> >>> Example A) Crystal pins connected to *PIN 9: A7/CLKIN* & *PIN 10: >>> A6/CLKOUT.* >>> >>> Example B) Crystal pins connected to *PIN 11: RC0/T1OSO *& >>> *PIN 12: RC1/T1OSI. * >>> >>> this make's me think that I'm connectin the crystal to wrong pins? >>> what's the difference between them? >>> >>> *2*. Maybe I need to try better with other cap values? >>> >>> *3.* Software getting the count wrong? >>> >>> Thanks a lot guys, I really appreciate your time and help. >>> >>> Christopher.. >>> >>> >>> >>> >>> >>> El jueves, 20 de mayo de 2021 a las 21:09:01 UTC+2, Dekatron42 escribió: >>> >>>> Since this is a Tuning Fork type of crystal they are sensitive to to >>>> much energy and might become damaged if you use them incorrectly. You >>>> should read this article: >>>> http://ww1.microchip.com/downloads/en/appnotes/91097a.pdf and also >>>> read the Microchip application note above that Bill van Dijk suggested as >>>> they both explain/discuss how to use this type of crystal. >>>> >>>> In this document for the PIC-processor in question: >>>> http://ww1.microchip.com/downloads/en/devicedoc/41364e.pdf they also >>>> mention the 91097a.pdf above as a document to read on page 71. >>>> >>>> /Martin >>>> >>>> On Thursday, 20 May 2021 at 20:40:49 UTC+2 MrThe50sanchez wrote: >>>> >>>>> Ei Martin! >>>>> >>>>> I'm using PIC16F1936 (16F family!) >>>>> >>>>> my connections are the following. >>>>> >>>>> Crystal pin 1 - RA7/OSC1/CLKIN/SEG2 >>>>> Crystal pin 2 - RA6/OSC2/CLKOUT/VCAP/SEG1 >>>>> >>>>> >>>>> I add you my pcb design (The old one) and the new one! >>>>> >>>>> (OLD ONE) >>>>> [image: old ddesign.png] >>>>> >>>>> >>>>> >>>>> NEW DESIGN >>>>> [image: new design.png] >>>>> >>>>> >>>>> Thanks a lot! >>>>> >>>>> El jue, 20 may 2021 a las 16:28, Dekatron42 (<martin....@gmail.com>) >>>>> escribió: >>>>> >>>>>> What PIC-controller is the crystal hooked up to? Did you follow the >>>>>> design specifications for using the crystal you chose? >>>>>> >>>>>> /Martin >>>>>> >>>>>> On Thursday, 20 May 2021 at 16:03:55 UTC+2 jf...@my-deja.com wrote: >>>>>> >>>>>>> All the cheap watches and clock movements seem to use the same small >>>>>>> cylindrical crystal. I got many of mine by taking them out of old >>>>>>> watches >>>>>>> or clocks that had stopped working properly (like worn out gears in a >>>>>>> clock). If you do not already have any in your junk box, you should be >>>>>>> able to buy a working one from a street vendor or flea market for under >>>>>>> € 5, and probably less than € 1. Also, new crystals will cost less >>>>>>> than US$1 each (plus shipping and handling), so you could buy several >>>>>>> and >>>>>>> select the one that works the best. >>>>>>> >>>>>>> On Wednesday, May 19, 2021 at 11:55:42 PM UTC-7 MrThe50sanchez wrote: >>>>>>> >>>>>>>> ? Any recommendations of where can I get a good quality cristal for >>>>>>>> my watch? >>>>>>>> >>>>>>> -- >>>>>> >>>>> 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+...@googlegroups.com. >>>>>> To view this discussion on the web, visit >>>>>> https://groups.google.com/d/msgid/neonixie-l/b9d34649-4fef-4fe8-a44b-8544b51dee8cn%40googlegroups.com >>>>>> <https://groups.google.com/d/msgid/neonixie-l/b9d34649-4fef-4fe8-a44b-8544b51dee8cn%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>> . >>>>>> >>>>> -- > 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 view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/b0456e09-3348-44d4-a2d5-5ec466983b82n%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/b0456e09-3348-44d4-a2d5-5ec466983b82n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. 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