r5821 - trunk/gta02-core/bom
werner at docs.openmoko.org
werner at docs.openmoko.org
Sat Feb 6 15:21:16 CET 2010
Date: 2010-02-06 15:21:16 +0100 (Sat, 06 Feb 2010)
New Revision: 5821
Added draft document describing some concepts and fields used for
characteristics. This is more to provide the background, not a straight
manual to follow.
This was written before I made any characteristics files for real
components, so some things differ. (E.g., there's no DSC field,
tolerances can also be absolute, etc.)
--- trunk/gta02-core/bom/CHARACTERISTICS (rev 0)
+++ trunk/gta02-core/bom/CHARACTERISTICS 2010-02-06 14:21:16 UTC (rev 5821)
@@ -0,0 +1,140 @@
+*** This is an older draft of the concept - differs sometimes from the way
+ things are done in gta02-core. ***
+BOMs are matched with inventories in the following way:
+- a .lst file with the BOM is generated by KiCad
+- using a ruleset, component characteristics are translated to a
+ canonical format and default values may be used for unspecified
+- part catalogs are searched for matches with the canonical component
+ descriptions. This yields a list of supplier-specific part numbers
+ for each component.
+ Parts can be characterized by either specifying their properties or
+ by equating them to another part. E.g., a Digi-Key part may be
+ defined as an NXP part which in turn is equivalent to a TI part.
+- this list is then matched against inventories, using a suitable
+ optimization strategy (e.g., prioritize inventories and try to
+ pick as many suitable components as possible higher priority ones
+ before moving to lower priority ones)
+ E.g., local stock could be the first-level inventory, followed by
+ more distant warehouses, followed by distributors, followed by
+ Inventories could also include pricing information.
+- TBD: it would be good if parameters gathered in the matching process
+ could be fed back into KiCad (as some sort of annotations, similar
+ to the expanded view of schematic symbols), such that under-specifed
+ parts yielding mismatches can be spotted by manual review.
+A catalog contains part characteristics and the reference number(s)
+assigned to them.
+Catalog entries consist of "words" in the sense that each word does
+not contain any whitespace and words are separated from each other by
+whitespace. Whitespace can be included in a word if it is enclosed in
+Each entry begins in the first column of a line. If an entry needs
+more than one line, the words on the continuation line(s) must be
+indented by whitespace.
+Trailing whitespace is ignored, and so are comments beginning with a
+hash mark. Blank lines end any entry and are also ignored.
+Each catalog entry begins with the part number followed by a part type
+Characteristics have the form <field>=<value>, where
+the fields follow the pattern outlined below. The value is some
+description of the value of that characteristic, typically a number
+and a unit (e.g., 4.7uF) or a name (e.g., X5R).
+Numbers use a decimal point where necessary. Mantissas are normalized
+such that they fall into the range 1 <= n < 1000. E.g., instead of
+0.1uF, write 100nF. There is no space between number and unit. The
+Omega of Ohm is written as "R".
+- - - - - - -
+H Height (overrides any height implied by footprint)
+TOL Tolerance, with percent sign. Split tolerances are indicated as n/m%
+DSC Free-format description
+- - - - -
+RES Part type designator
+R Resistance, with unit
+P Maximum power dissipation
+V Maximum volatage
+- - - - -
+CAP Part type designator
+C Capacitance, with unit
+M Material, e.g., TANT, NP0, X5R, etc.
+V Maximum voltage
+ESR ESR, with unit
+-- - - -
+- - -
+DIODE Regular diode
+STKY Schottky diode
+Vf Maximum forward voltage
+Vr Maximum reverse voltage
+If Maximum forward current
+Ir Maximum reverse current
+LED Ligh-emitting diode
+COL Color, multiple colors are separated by /, e.g., blue/red
+ARRAY If multiple diodes form an array, this parameter describes
+ its structure: CA = common anode, CC = common cathode,
+ SEQ = tap-A-C-tap-A-C-tap sequence
+ZENER Zener diode
+Vz Zener voltage
+TVS Transient voltage suppressor
+Vac Working voltage, AC
+Vdc Working voltage, DC
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