Optional Pullup (simple)

Ok im trying to save space on a PCB and also save on parts by making a few pullups OPTIONAL.. The question i have is... instead of me having a JUMPER on each line... can i just have them all connect to one VCC2 and a jumper to VCC1 connect them both...

Basically will having partially connect resistors pose a issue? I doubt they will but dont want to take the chance.

Thanks

Are you describing having multiple port pin pullups tied to the ports, but leaving the Vcc end (common to several pullups) floating? If so, that might not be a good idea...

Yeah, i just understood why right now

The other pin can pull one high when not needed... I removed that idea from the board and just omitted the pull-ups entirely

AtomSoft said:

Yeah, i just understood why right now

The other pin can pull one high when not needed... I removed that idea from the board and just omitted the pull-ups entirely

Click to expand...

If you were to do it that way the answer would be to ground the other end - so selectable as either pull-ups or pull-downs.

Hey Nigel, yeah i planned to use a solder jumper, but i simply took them out since it is for a i2c bus and i only need one pair anyway which i plan to have on the main pcb. Its ok tho... Thanks

Will a SIP network help? or Two SIP networks? One for the pull-up and one for the pull-down. Snip the pin your not using.