gEDA : Try Me

This is not a line from a Dirty Harry movie. Although Harry Calahan might have uttered something similar. Try Me is a small gEDA circuit that has

as you can see on the right. It's purpose is to test newly designed parts (aka symbols) to see whether their power grip matches with the rest of the circuit. And to test the numbering scheme.

The connector is there so that the software (should it check for such things) thinks that the power grid is not made onboard but supplied via a kind of connector. The rest is all there to fool the other tools and tyo make sure some kind of Vcc/Gnd network is available.


TryMe1 : test the DS1233 and OscillDip14 symbols

The new circuit is on the right. The two new parts are included. After saving the schematic, it is time time create the numbers for the parts with refdes_renum and subsequently create the netlist and such with the gsch2pcb program. Let's see how this goes: 

jan@Beryllium:~/geda/TestMe$ refdes_renum TryMe1.sch
Scanning input file #1: TryMe1.sch
Now processing input file #1: TryMe1.sch
Check it with 
gschem TryMe1.sch
to convince yourself that the parts have numbers now. But you can also take a look at the circuit on the right.

Now is the time to run gsch2pcb. This is an intermediate program. It runs several other programs, like the netlist creator: 
jan@Beryllium:~/geda/TestMe$ gsch2pcb TryMe1.sch
Done processing.  Work performed:
0 file elements and 6 m4 elements added to TryMe1.pcb.

Next step:
1.  Run pcb on your file TryMe1.pcb.
    You will find all your footprints in a bundle ready for you to place
    or disperse with "Select -> Disperse all elements" in PCB.

2.  From within PCB, select "File -> Load netlist file" and select
    TryMe1.net to load the netlist.

3.  From within PCB, enter

           :ExecuteFile(TryMe1.cmd)

    to propagate the pin names of all footprints to the layout.
So, it's hard to the upcoming things wrong. They're spelled out for you! Only step 3 I haven't been able to perform at the moment.

In the very first trial PCB, the DS1233 had pins 1 and 3 reversed. That was bad. So after changing the library and redoing the circuit, the next test showed that the power lines were now attached correctly.

In the second test the Vcc line was not conencted. Reason: the net was called 'VCC' whereas the gEDA net is called 'Vcc'. After updating the library, the problem was solved.

In the third experiment it showed that the oscillator only had pin 1 connected. Why was that? The footprint is called 'OSC14' and I had assigned pinnumbers 1, 7, 8 and 14. After some testing this seemed to be the reason. After renaming the pins 1, 2, 3 and 4, the problem was solved.


Page created on 17 March 2011 and

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