Joris Posted February 26, 2010 Report Posted February 26, 2010 Met een basiskennis elektronica, geen expert dus... tracht ik de Dinx4 print aan te passen aan mijn behoeften en wat te optimaliseren. Daarbij ontdek ik een (groot) aantal zaken die me toch vragen doen oproepen : De verschillen tussen schema en de print (betreft 74HC165) : In schema : pin 16 met condensator naar de aarde ? Op print : pin 16 met condensator naar pin 10 (verder naar +5V) Volgens schema zou ik op de print dan : pin 16 met condensator naar pin 15 verbinden, die naar de aarde gaat. Verder worden die pull-up weerstanden gewoon niet op de print voorzien (R33 tot R36), zijn die dan helemaal niet nodig ? Hadden die geen nut bij een configuratie met minder 74HC165 op die print ? Wat is er fout of slecht geconfigureerd, het schema of de print ? http://ucapps.de/mbhp/mbhp_dinx4.pdf http://ucapps.de/mbhp/mbhp_dinx4_v2.brd Quote
nILS Posted February 26, 2010 Report Posted February 26, 2010 Caps: The bypass caps are missing in the layout and need to be soldered to the underside (between the supply pin of each IC and ground, ie between pin 16 and the nearest ground pin which is pin 15). See the note in the pdf "The bypass caps C1..C4 are placed on the bottom side of the PCB" Pullups: You do need the pullup resistors. I am not sure what you mean by "they are not equipped". They're mounted vertically next to the 5-pin headers (where it says 10k). Quote
Joris Posted February 26, 2010 Author Report Posted February 26, 2010 Caps: The bypass caps are missing in the layout and need to be soldered to the underside (between the supply pin of each IC and ground, ie between pin 16 and the nearest ground pin which is pin 15). See the note in the pdf "The bypass caps C1..C4 are placed on the bottom side of the PCB" Pullups: You do need the pullup resistors. I am not sure what you mean by "they are not equipped". They're mounted vertically next to the 5-pin headers (where it says 10k). nILS thanks, I confused the vertically mounted pullup resistors with the caps (they should be around the same position normally). I think I've got it now. Seems there is even more possible to optimize as those resitors give more room to be positioned. Quote
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