Multiple pads same signal, jumpers, remove pins, multiple trace widths...

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KurtEck
Posts: 18
Joined: 15 May 2011, 05:55

Multiple pads same signal, jumpers, remove pins, multiple trace widths...

#1 Post by KurtEck » 09 Oct 2019, 05:08

As a hobbyist, I have now used DipTrace for maybe 7+ years now on an occasional basis as I do my own relatively simple boards, many of which are geared around Teensy T3.x and T4 processor boards by PJRC.

Please pardon in advance that I know I or others have asked many of these questions in past.

Each time I develop a new board, I keep running into some of the same issues over and over again. Some of which I have asked in the past, but at those times there did not appear to be any easy solutions. But it has been a few years and a few releases and maybe I have missed some new feature that solves some of these.

Suppose right now I am designing a new board for the new Teensy 4: https://www.pjrc.com/store/teensy40.html

a) Same Signal on multiple Pins/pads: On this chip there are a few different signals such as Ground and 3.3V pins, that normally when I say connect all of the GND pins to the GND net, the system will want to run etch between all of these pins... Is there now some way to say there is an internal connection between these pins, such that the system will not either automatically route etch between them or complain where there is not any etch there?

b) remove unused pins/pads: On The T4 (T3.2...), A lot of the time you may not choose to use all of the IO pins. Example most of the main signals are in two rows of 14 pins (.6" apart). At the one end there is an addition 5 pins that run between these two rows, in this case (ON/OFF, Program, GND, +3.3V, VBat). On several boards I may choose to not use some or all of these pins and remove them to make it easier to route the board. Currently I do this by making diplicates of the patterns and components with the different pins removed. But was wondering if there was another way? You can easily end up with many combinations of pins, like I may only want the VBat there or maybe also On/OFF. And then there are some other sections of pins, like some surface mount pins 2x5 that I may or may not want, likewise for USB Host connections, and maybe SD card connections...

c) Solder Jumpers: Sometimes I would like to have solder jumpers, Example maybe I want my card to handle an SPI device like a display and I may wish to set up the board to be able to have the display on the SPI object (Pins: 10-13) or maybe SPI1(0,1,26,27), assume default to SPI. So would like to put in 4 3 pad jumpers where the center pad runs to the connector for the display and you run the two IO pins to the other pads... If I remember correctly Sparkfun had some of these defined in their Eagle libraries, but whenever I tried it, it complained about shorts, or clearance issues or other such issues. Any current suggestions? At one point I did this by setting up to have some 0403 like resistors defined, but that is not optimal.

d) Having one NET with multiple desired trace widths... Example GND - With some of the main components, like connections to power connector or going off to display or ... I often want a wider trace, example 60 mills, but then there are lots of other components, example an 0805 decoupling capacitor which also needs to connect to ground, that that can be done with a standard width, example 8mil. Is there any easy way to automatically set this up, such that the auto-router can know about this and route these differently, but still know they are the same net? Normally I end up, maybe hand routing, the large ones, then try the autorouter, which still has the large setting, which often fails, and then either fix by hand or then try to tell the net to be 8 mill and run router again...

Again sorry if all of these have been asked in the past, but hoping I have missed some new things that help out with some of these.

Thanks again

Serg
Technical Support
Posts: 519
Joined: 09 Jun 2010, 01:12

Re: Multiple pads same signal, jumpers, remove pins, multiple trace widths...

#2 Post by Serg » 10 Oct 2019, 01:31

Thank you for offers. We will consider them and the more actual ones will added to our to do list.

SoundMod
Posts: 77
Joined: 15 Feb 2016, 05:47

Re: Multiple pads same signal, jumpers, remove pins, multiple trace widths...

#3 Post by SoundMod » 22 Oct 2019, 04:50

KurtEck wrote: 09 Oct 2019, 05:08 a) Same Signal on multiple Pins/pads: On this chip there are a few different signals such as Ground and 3.3V pins, that normally when I say connect all of the GND pins to the GND net, the system will want to run etch between all of these pins... Is there now some way to say there is an internal connection between these pins, such that the system will not either automatically route etch between them or complain where there is not any etch there?
If I did understand correctly, simply draw polygon shape on the restrict layer to constrain copper pouring on some area of your design.
While I'm talking about the restrict layer I have a suggestion for the Diptrace team, I think you should move restriction object as restriction layer, I mean restrict should appear has layer instead of object on copper layers. Also having restriction as filled object is a bit annoying (could we change the opacity of them or put the fill as hatch or dot pattern instead of filled color).
KurtEck wrote: 09 Oct 2019, 05:08 b) remove unused pins/pads: On The T4 (T3.2...), A lot of the time you may not choose to use all of the IO pins. Example most of the main signals are in two rows of 14 pins (.6" apart). At the one end there is an addition 5 pins that run between these two rows, in this case (ON/OFF, Program, GND, +3.3V, VBat). On several boards I may choose to not use some or all of these pins and remove them to make it easier to route the board. Currently I do this by making diplicates of the patterns and components with the different pins removed. But was wondering if there was another way? You can easily end up with many combinations of pins, like I may only want the VBat there or maybe also On/OFF. And then there are some other sections of pins, like some surface mount pins 2x5 that I may or may not want, likewise for USB Host connections, and maybe SD card connections...
This one I'm not sure, but if it is related to a component in schematic you can mark pins has Not Connected, this will put an X on it. However, if it is related to the PCB layout and if you are really saying that you are removing copper pads of unused pins to make space for trace I would say that this is a bad practice.
KurtEck wrote: 09 Oct 2019, 05:08 c) Solder Jumpers: Sometimes I would like to have solder jumpers, Example maybe I want my card to handle an SPI device like a display and I may wish to set up the board to be able to have the display on the SPI object (Pins: 10-13) or maybe SPI1(0,1,26,27), assume default to SPI. So would like to put in 4 3 pad jumpers where the center pad runs to the connector for the display and you run the two IO pins to the other pads... If I remember correctly Sparkfun had some of these defined in their Eagle libraries, but whenever I tried it, it complained about shorts, or clearance issues or other such issues. Any current suggestions? At one point I did this by setting up to have some 0403 like resistors defined, but that is not optimal.
Right now I will say just ignore the DRC error, however I must admit that will be a great feature to be able to specifically tell to Diptrace: ''Those nets connect through a jumper don't throw error''. Another feature which I think could be great related to this would be to be able to have several GND type (as example: A_GND, D_GND, COM_GND) on the same schematic but being able to connect them into ONE point (ground star connection fashion) without getting DRC error. Right now the only way I got this to work was with the use of jumper resistors which is annoying.
KurtEck wrote: 09 Oct 2019, 05:08 d) Having one NET with multiple desired trace widths... Example GND - With some of the main components, like connections to power connector or going off to display or ... I often want a wider trace, example 60 mills, but then there are lots of other components, example an 0805 decoupling capacitor which also needs to connect to ground, that that can be done with a standard width, example 8mil. Is there any easy way to automatically set this up, such that the auto-router can know about this and route these differently, but still know they are the same net? Normally I end up, maybe hand routing, the large ones, then try the autorouter, which still has the large setting, which often fails, and then either fix by hand or then try to tell the net to be 8 mill and run router again...
Suggestion here for Diptrace team, on the manual autorouter user could setup in the preference of diptrace or in the interactive router to select a smaller trace (should follow the rules of nets class and trace template) if an area is populated with too much object, as soon as the user trace leaves that area it automatically goes back to the width which was define previously.

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