Re: gEDA-user: Gschem and footprints

[Colin D Bennett <colin@xxxxxxxxxxx>]

On Tue, 16 Aug 2011 15:35:46 -0500 (CDT)
kqt4at5v@xxxxxxxxxxx wrote:

> I am sure this has been done to death but I have to ask
> I am a beginner and the way I am using gschem and pcb is quite awkward
> I open my schematic in gschem and open pcb
> Then when I add a component in gschem I switch to pcb to search for a
> footprint When I find the proper footprint in pcb I switch back to
> gschem and manually edit the properties to add the footprint name
> I MUST be doing something wrong

You're not doing anything âwrongâ.  There are many ârightâ ways of
working with gEDA... it allows you the freedom to choose what works
best for you. If switching back and forth between pcb and gschem is
tedious, then consider the following suggestions as just a few of the
possible optimizations you can make to your process.

I almost never use pcb's footprint browser.  Yes, the default pcb
footprint library has a lot of symbols with obtuse names, so it is
difficult to find the one you need by name.  However, I only use a few
of the default footprint library's footprints--for instance: JUMPER4,
RESC1608N, CAPC1608N, ... and most of my footprints are custom ones I
have created myself.

The footprints in my own library have extremely descriptive names and
all I need is a file manager window listing the available footprint
files and I can pick the correct footprint by name.  For instance, here
are some footprint file names from my library:

Abracon_ABM8G.fp
ADAM_TECH_2PH_2.00_mm_pin_header_SMT_2_pin.fp
ADAM_TECH_2PH_2.00_mm_pin_header_SMT_3_pin.fp
ADAM_TECH_2PH_2.00_mm_pin_header_SMT_4_pin.fp
Antenna_Inverted_F__Ember__2.4GHz__62milFR4.fp
Antenna_Meandered_Inverted_F__2.4GHz__TI_AN043.fp
APEM_MJTP1230_6mm_tactile_switch__4pin.fp
APEM_MJTP1230_6mm_tactile_switch__P1_P4.fp
Bourns_3309W-1_Trim_Pot.fp
Castellated_Via__D20mil_W36mil_L40mil.fp
Castellated_Via__D45mil_W60mil_L50mil.fp
CK_KMT0.fp
DFN8_2x3_Microchip_MC.fp
DPAK_Pin2IsTab.fp
DPAK_Pin4IsTab.fp
FCI_10033526-N3212MLF.fp
FCI_98424-x52-06.fp
Header_1x3_100mil.fp
Header_2x10_100mil_rcnum.fp
Header_2x3_100mil_rcnum__with_IDC_receptacle_outline.fp
Hirose_DF13A-2P-1.25H.fp
Kemet_EIA_6032-28_DensityB.fp
Kingbright_SA56-11EWA.fp
Kingbright_SA56-11EWA__Oval_pads__Max.fp
LED1608M_logical_pins.fp
Molex_KK-156_male_header_3pin.fp
Molex_KK-156_male_header_8pin.fp
MSOP8_Microchip_MS.fp
Murata_CSTCE.fp
Murata_LDB18.fp
Nichicon_Aluminum_Electrolytic_Capacitor_UX_10x10.fp
NKK_UB_Pushbutton_SK_SPDT.fp
NXP_LQFP-48_7x7_SOT313-2.fp
Omron_XF2M-2015-1A_RefPin1.fp
Omron_XF2M-2015-1A_RefPin20.fp
Optek_OVS5MxBCR4_LED.fp
OSRAM_LA_LS_LY_E65F_LED__IR_reflow.fp
OSRAM_LR_LY_T68F_LED__basic_reflow.fp
OSRAM_M676_LED.fp
Phoenix_Contact_1984620__Pin1OnRight.fp
QFN32_5_EP_multi_opening.fp
R_0603_Walsin.fp
SOIC-8N_Exar_IntelGuidelines.fp
SOT-23_Microchip_TT.fp
SOT23__MOSFET_1G_2S_3D.fp
SOT353_NXP.fp
SOT-89_Microchip_MB.fp
SSOP-20_Microchip_SS.fp
SSOP-28_FTDI_IntelGuidelines.fp
ST_LQFP48.fp
Tag-Connect_TC2030-MCP.fp
Tag-Connect_TC2030-MCP-NL.fp
Tag-Connect_TC2030-MCP-NL_PlatedHoles.fp
Tag-Connect_TC2030-MCP_PlatedHoles.fp
Test_Pad_0.8mm.fp
Test_Pad_1.0mm.fp
Test_Pad_1.27mm.fp
TSOP-5.fp
Tyco_1734035.fp
Vishay_Dale_XT49M_SMD_crystal.fp

You should be able to understand the purpose of each footprint by its 
nae and perhaps a quick Google on the package code or part number.

I also occasionally have used footprints from gedasymbols.org.  The
gedasymbols.org web site has a great interface for searching the
footprint library and previewing the footprints.

Another thing you can do to save time is to defer footprint attribute
assignment until you have the schematic mostly drawn.  Then you can do
footprint assignment quickly.  You can use either gschem or the
âgattribâ tool to quickly assign footprints to all symbol instances
in a schematic.

I highly suggest you become proficient at creating your own footprints
since you will often run into new parts without a pcb footprint, and
this allows you to keep a consistent footprint style matching your own
preference (you might have your own preference about silk screen
outline style, etc.).  Creating footprints was tedious for me at first,
but now after making several dozen, it has become really simple.  I just
grab a calculator (or the qalculator application), a pencil and paper,
and lay out the footprint per the manufacturer's package drawing and
recommended land pattern.  I usually create the footprint file (*.fp)
with a text editor since it's easy to get the exact layout that way,
but on occasion I will use pcb to draw the footprints graphically, or
make minor edits to hand-made footprint files.

This is surely not exactly the type of answer you were expecting, but
gEDA is such a flexible tool that there is no single right answer...

Regards,
Colin


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