I can't route pads for certain components

[nick38]

If I click the "Interactively Route Connections" and then I place the cursor near the center of the pad for certain components the cursor will snap to the center of the pad and a green circle will apear on the middle of the cursor. So I left click to start routing but the trace does not appear. Instead the circle dissapears and the cursor snaps off the center of the pad. Why is this happening? and how can I fix this?

[WhoKnewKnows]

My first thought is that the trace width is too large for the rules to allow the trace to start from the center point of the pad. If you initiate routing as you've described, then press tab to pause routing and view the properties panel. There you can adjust the trace width to something narrower that works with the rules. Just a guess.

[nick38]

I tried changing the track width but it still does the same thing. It seems like only the ground pads are affected.

[WhoKnewKnows]

Depending on the rule settings, Altium may not allow you to set the track width narrow enough. There's a minimum, maximum and preferred width that can be assigned per net or per layer or, etc. When you start a track on a pad, the net and layer are automatically set. Then, the width you can set from this point can't go below the minimum allowed by rules, but, that minimum still may not be narrow enough to satisfy clearance rules, and it may be the clearance rules that are preventing routing from taking place. place.

[WhoKnewKnows]

Also, I wonder why pin 9 doesn't have a net assigned. In some cases it can be left unassigned, but it's typically assigned ground. Experimentally, you might select it and manually assign it the ground net. Then, see if it gets easier to start a route from pin 4 or 5.

[nick38]

Yes! I changed the track width from the menu Design->Rules->Routing->Width the minimum width was set to 0.254mm and the width of the pad was also 0.254mm.
I'm not sure if I should create a new rule for Ground and VCC or only modify this default rule. What width would you recommend me to use? 0.2mm?
I forgot to connect pin 9, it also goes to ground.
Thanks!

[WhoKnewKnows]

Oh good. Glad you got going.

Routing width depends on what the IC is for. Signals usually don't need much width, but power tracks usually want a little more. The higher the current the wider and shorter the path wants to be

[WhoKnewKnows]

Going too narrow tends to cost more at the fab shop.

6 mils (0.154mm) and larger should be pretty easy for any shop to make.

[Paul van Avesaath]

finally somebody is talking mills again ... its been too long.. 😁

[robertferanec]

nick38, before routing you need to set the basic rules such minimum track width, minimum clearance, minimum via hole, minimum via pad, mask clearance. If you don't know what to use (or if you can't find that information on your PCB manufacturer website), you can use for example the numbers from JLCPCB website, just search for "jlcpcb capabilities":

https://jlcpcb.com/capabilities/pcb-capabilities

[WhoKnewKnows]

I knew you'd be along, robertferanec. I imagine you've got a video course they could follow about this too, right?

[qdrives]

One thing I heard someone state is that when all the rule(s) are disabled (or missing), it may be impossible to change the dimensions. In the reported case it were the via hole and pad sizes.
I do not know if that helps as when I try it, it works correctly.

[WhoKnewKnows]

Did someone state that in this thread? I don't remember seeing that claim.

[qdrives]

"...I heard someone state..." not on this thread no. It was somewhere else (in live person).

[robertferanec]

I knew you'd be along, robertferanec. I imagine you've got a video course they could follow about this too, right?

The basic process is also included in my ESP32 video: https://www.youtube.com/watch?v=S_p0YV-JlfU&t=4839s