DIN Module questions

Design Concepts
1

Hi !

I’m new on this site, and have some questions about the DIN Module. I made my own before I checked the schematics from this site, and it is a little bit different:

so the questions are:

  1. Why don’t you use Resistor-Networks? They are easy to handle, and reduce the board size.

  2. Is it better to use pullup  instead of pulldown resistors on the input of 74hc165?

Thanks

Maik

2

Hi Maik,

  1. Why don’t you use Resistor-Networks? They are easy to handle, and reduce the board size.

everbody is allowed to use resistor networks if he wants, the reason why the PCBs are stuffed with common resistors is, that I have to ensure that the parts are worldwide available for low prices (not every mailorder company sells resistor ladders).

The first version (from 1999) was stuffed with resistor ladders, but I removed them on request

  1. Is it better to use pullup  instead of pulldown resistors on the input of 74hc165?

Yes, the advantage is, that buttons, rotary encoders, etc… can be connected to ground. This is mostly easier to handle once they are mounted on a metal panel. Another advantage is, that the pin used for ground can be connected together with the cathode of LEDs (LEDs are driven high-active in my designs)

Best Regards, Thorsten.

P.S.: I’m missing the bypass caps! :wink:

3

I only use bypass caps on µC… on simple logic ICs they are pretty useless… may be that I’ll use one for each board

By the way, I found out that my board has a big disadvantage… I’d to make 32 cables for each board…that’s a stupid work  ;D Next time I’ll route all input pins to one big connector, with only one 5V-supply-pin (on your board it would be ground).