[kicad-users] 7805

[Kerry Koppert [e-mail] [kicad-users]]

I'm a real newbie with kicad, shifting from Eagle, so excuse me if I ask
dumb (and often asked) questions. I am trying to come to grips with the
split of a component into two entities. I try to use a 7805 voltage
regulator and place that in the schematic. When it comes to moving from
schematic to board I run cvpcb to associate the 7805 with a footprint.
The obvious one to select is a to-220 vertical. When I go to pcbnew and
read the netlist it bitches about the pads vo, gnd, vi and the 7805 sits
on the board not connected to anything. I guess the schematic uses vi,
gnd and vo for the pinnames whereas the footprint uses 1, 2 and 3. How
do I associate the pins? Do I have to create a new footprint to-220_7805
with the pins relabelled?

[Andrey Kuznetsov [e-mail] [kicad-users]]

Did you run ERC in eeschema before exporting the net list? Where there any
errors? Need to fix those errors first.

Post by Kerry Koppert ***@xtra.co.nz [kicad-users]
I'm a real newbie with kicad, shifting from Eagle, so excuse me if I ask
dumb (and often asked) questions. I am trying to come to grips with the
split of a component into two entities. I try to use a 7805 voltage
regulator and place that in the schematic. When it comes to moving from
schematic to board I run cvpcb to associate the 7805 with a footprint.
The obvious one to select is a to-220 vertical. When I go to pcbnew and
read the netlist it bitches about the pads vo, gnd, vi and the 7805 sits
on the board not connected to anything. I guess the schematic uses vi,
gnd and vo for the pinnames whereas the footprint uses 1, 2 and 3. How
do I associate the pins? Do I have to create a new footprint to-220_7805
with the pins relabelled?

[Andy Eskelson [e-mail] [kicad-users]]

Hi Kerry, welcome to the group.

Kicad is a little bit different in this respect, it also highlights one
of the dangers of community based device libraries.

The pins of the device on the circuit AND on the footprint MUST be
the same. either numeric (the normal method) or some names.

I usually use numbers, so just editing the footprint is all that would be
needed.

This will also be the cause of the not connected errors. Basically Kicas
sees the 1,2,3 on the netlist, but can't find them on the module.

With Kicad, (this is true for any CAD system as well) you should ONLY use
devices and modules that you have verified as correct and placed in your
own lib directories. That saves so many headaches in the future, so start
now :-)

Also once you edit a module once it's saved in your own libs you don't
have to change it again.

99% of the online modules are Ok, but everyone has their own
requirements, and some might not suit your needs, so always best to check.

The biggest danger is if a module gets updated/changed and you don't
notice when you make your next project, or make a change to an existing
project. It's annoying on a one or two chip home project, but can be a
disaster on a larger commercial design.

As a beginner the next thing you are likely to run into is a pin not
powered error when you run the ERC in escheema.

The ERC rules look for inputs connected to outputs, and power in and
power in connected to power out.

In some cases the circuit device such as a three pin regulator will have
the output pin designated as a power out. Personally I don't like this
and I always change this to be passive.

In many cases a PCB is powered for off board, such as from a wall wart
PSU, so the board does not actually have any power providing devices on
it.

the way you deal with this is to first add power ports to the circuit
9you have probably already found these, they are the +12, +5 "pins" that
you can add to various parts og your circuit to ease the drawing of
power traces.

You then need to tell ERC that these are actually powered (this is the
trap that most beginners fall into) To do that you add a power flag to
the power trace concerned, on on the +5 one on the +12 and so on.
The power flag just tells ERC that the particular power net is in fact
powered and ERC is then happy.

One oddity is that the ground net is also considered a powered net so
that needs a power flag as well.

There must ONLY BE ONE power flag on a power net. If you have a device
with a pin type set to power out, that acts as a power flag, and
obviously if you add a flag yourself, ERC will then complain. This is
why I don't set pins as power out.

I usually put a set of power ports in one corner of the circuit diagram
and add a short connection line to them, then add a power flag to each. I
then know that all the nets are powered.

Another tip, if you can't seem to find a particular function, check the
right click context menu, you will often find what you are looking for
there.

You will prob. have more questions as you work through Kicad. Feel free
to ask for help - we have all gone through the process :-)

Andy







On Sun, 23 Apr 2017 13:10:10 +1200

Post by Kerry Koppert ***@xtra.co.nz [kicad-users]
I'm a real newbie with kicad, shifting from Eagle, so excuse me if I ask
dumb (and often asked) questions. I am trying to come to grips with the
split of a component into two entities. I try to use a 7805 voltage
regulator and place that in the schematic. When it comes to moving from
schematic to board I run cvpcb to associate the 7805 with a footprint.
The obvious one to select is a to-220 vertical. When I go to pcbnew and
read the netlist it bitches about the pads vo, gnd, vi and the 7805 sits
on the board not connected to anything. I guess the schematic uses vi,
gnd and vo for the pinnames whereas the footprint uses 1, 2 and 3. How
do I associate the pins? Do I have to create a new footprint to-220_7805
with the pins relabelled?
------------------------------------
------------------------------------
Please read the Kicad FAQ in the group files section before posting your question.
Please post your bug reports here. They will be picked up by the creator of Kicad.
Please visit http://www.kicadlib.org for details of how to contribute your symbols/modules to the kicad library.
For building Kicad from source and other development questions visit the kicad-devel group at http://groups.yahoo.com/group/kicad-devel
------------------------------------
Yahoo Groups Links

[[e-mail] [kicad-users]]

Excellent reply, Andy.

Kerry, How newbie are you? I have a screen full of matchbox size projects and still consider myself a newbie. Kicad has a steep learning curve. My solution is likely to get me banned from the group, but it works for me. Draw a schematic with one PWR_FLAG, one GND, and one CONN_01X01 connector. Create a footprint module with one oval pad 0.08 x 0.55 inch and a 0.032 inch hole. Save to a "library" starting with a zero to place the footprint first in any list. Save .pretty to 'current project only' and to your folder of Kicad libraries. Run annotate, ERC, net, and CvPcb stopping when you can place the new 'net' on Pcbnew board.

Save and write protect the project folder to same folder as your saved Kicad 'libraries'..

Copy your protected folder to your desktop and change the folder name and all contained file names to your new project name.

Open Pcbnew of the new folder. Link the one pad footprint in 'Preferences' 'Footprint Library Wizard' and DISABLE 'design rule checking'.

For very simple boards, place your one pad footprint on the board and 'Block Copy' several times to create a stack of pads. Move the pads where needed on the board. Join with top and bottom tracks and vias, then edit both tracks and pads until it meets your requirements including adding GND to net names of additional gnd pad's . Keeping one GND pad on the board at all times maintains the ability to specify one surface as a ground plane. Place graphics where they won't get in the way.

'Perform the design rules check' and look for tracks too close together and anything that is not 'Track near pad'. If one end of all tracks has a marker, you are about finished.

Complete all remaining processes to create the final .zip file.

You alone are responsible for any design errors that get past the fabricator's rules checker and this did bite me once but nothing that a tombstoned smd resistor and short piece of wire didn't fix. It was a good chance that the error would have occurred in the schematic stage and might have been caught creating the pcb. Who knows.

When you are more familiar with the Kicad process, and certainly going beyond the newbie stage, create well designed schematics and take a position on protected libraries vs. cloud libraries.

Attachment: three what did I miss inspections before board for one of three, SN74HC165N shift register and sockets for switches, to be strung across panel, goes to the fabricator. Used Socket_Strip_Straight_1x08, R_0805, and SOIC-16_7.5x10.3MM_Pitch1.27mm and footprints from generic footprints. Nice job on all.

Oh yeah, tie a piece of thread to pin#1 of chips and a different colour thread to a major pin on same bank of pins of square devices to maintain orientation when chip is when flipped or rotated. When routing becomes a problem, draw a circle around the destination pin.

Hugh

[Peter Bennett [e-mail] [kicad-users]]

I suggest making new footprints with the pin numbers matching the
schematic symbol - copy the TO-220_Vertical footprint, rename the pins
as appropriate, and save the modified copy as TO-220_vertical_7805.

For small transistors, you might have TO92-ebc, TO92-ecb, TO92-GDS,
TO92-78L05,.. etc.

Post by Kerry Koppert ***@xtra.co.nz [kicad-users]
I'm a real newbie with kicad, shifting from Eagle, so excuse me if I ask
dumb (and often asked) questions. I am trying to come to grips with the
split of a component into two entities. I try to use a 7805 voltage
regulator and place that in the schematic. When it comes to moving from
schematic to board I run cvpcb to associate the 7805 with a footprint.
The obvious one to select is a to-220 vertical. When I go to pcbnew and
read the netlist it bitches about the pads vo, gnd, vi and the 7805 sits
on the board not connected to anything. I guess the schematic uses vi,
gnd and vo for the pinnames whereas the footprint uses 1, 2 and 3. How
do I associate the pins? Do I have to create a new footprint to-220_7805
with the pins relabelled?
------------------------------------
------------------------------------
Please read the Kicad FAQ in the group files section before posting your question.
Please post your bug reports here. They will be picked up by the creator of Kicad.
Please visit http://www.kicadlib.org for details of how to contribute your symbols/modules to the kicad library.
For building Kicad from source and other development questions visit the kicad-devel group at http://groups.yahoo.com/group/kicad-devel
------------------------------------
Yahoo Groups Links