Abstract: A clock circuit (12) normally couples clock pulses to a microprocessor (11), which is capable of accessing memory devices (13,14) having different access times. Access of a "slow" memory device 14 is detected by the clock circuit, and in response thereto, one or more clock pulses are not coupled to the microprocessor. This suspends operation of the microprocessor for a suitable amount of time so that the microprocessor reads valid data from the slow memory device. The number of clock pulses blocked from reaching the microprocessor can be set in a delay circuit (28) in the clock circuit.

Abstract: A page printer (101) which rasterizes a page utilizing partial page bit map swaths. Received data to be printed is stored in packets (12-17) in a page buffer in random access memory (105). Data within each packet is arranged in printing order down the page to be printed, but the packets themselves are arranged in the order received, and are not indexed or linked. As each swath (11) is rasterized, each packet is examined, and packets containing data falling at least in part within the active swath are processed. The printer is controlled by a programmed microprocessor, and logic hardware assistance is provided for translating data addresses from logical addresses (54) to physical addresses (52). Logic hardware assistance is also provided for making the determination of whether or not a given data address lies within the active swath.

Abstract: A printer having a print engine (13) and a bit map memory (12) including a number of page image areas (31) into which information to be printed is rasterized and from which information for the print engine is serialized. A digital processor (11) controlling the print engine is operable to reduce a page image area (31) to a modified page image area (37) based upon the highest and lowest addresses at which information has been written into the page image area. The digital processor (11) is also operable to begin rasterization of a new page image area when a sufficient amount of an existing page image area (41) has been serialized to make available the requisite bit map memory for the new page.