Component Graphics Generation is a process through which the schematic diagram acquired from PCB reverse engineering and generate to graphic simbol After parsing the schematic component library, the ASCLL code represented by all components in the component library is converted into characters and imported into the corresponding database table.
generate to graphic simbol After parsing the schematic component library
In the database, the component table is created with 9 basic graphic elements with each parameter as the field name, and the component package name index table is created. When the ASCLL code is imported into the database, the component package name and the corresponding graphic element number are imported into the package name index table, and the component parameters are imported into the corresponding graphic component table.
According to the internal representation of the Protel schematic library, you can know the meaning of each field in each basic graph table. To get the symbol graphic of a component, use the component package to search the database. After finding the component, draw the graphic according to the meaning expressed by these parameters.
Protel schematic library
It is possible for a component to have multiple component descriptions in a component library. For example, in the above component library, Z8601, Z8611, Z8603, Z8613, Z8671, Z8781 and Z86C11 all use a schematic package DIP-40. At address E360, the header of all components, the value in the first two address locations of Z8601 is 07, indicating that 7 components are in the same package, at the address E3A0 is the start address of the component package, at the E820 address Is the end address of the component package. The specific component search process is as follows:
- Indexing based on component packages in the component library;
- Lookup based on the component package in the index table. If the search is unsuccessful, an error is reported and the need to add the component graphic to the Protel component library;
- Search the corresponding comparison between the string of the component package name given in the network table and the string in the library file to find the exact same string;
- Find the address of the next identical string in the same search method;
- Determine whether the first two characters of the string are numbers. If it is not a number, look forward until the number in front of the string is not equal to the length of the string, and use the string as a string to determine the internal definition of the component. Judgment mark
