| 摘要 |
Method and apparatus to enhance laser printer speed and functionality including a general purpose computer, a laser printer, and a modified laser printer font cartridge, comprised of a 21-bit wide address bus, a read-only data bus, a page register, an address counter, a data counter, a font ROM module, an address-to-data converter, and a co-processor. The address bus is coupled to the laser printer and carries either address information to access locations in the co-processor or the font ROM, or data to be input to the co-processor. When the address bus carries only address information, the quantity of accessible memory locations is increased by mapping the contents of the page register with the bit code carried by the address bus. Thus, font pattern data may be read from the font ROM memory location represented by the combination of the page register contents and bit code carried by the address bus. However, if special information is loaded into the data counter, then the information carried by the address bus is actually data to be written to the co-processor. The data is transferred from the address bus, by the address-to-data converter, to the location in the co-processor represented by the combination of the contents of the page register and the address counter. The data bus is coupled to the laser printer and carries either processed font pattern data from the co-processor, or unprocessed font pattern data from the font ROM to the laser printer.
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