This invention relates to data processing method, and data processor and printer using the data processing method and, more particularly to a data processing method which is used when image data is received from a host computer and printing is performed based on the received data, and data processor and printer using the data processing method.
In recent years, the printing resolution of printers has increased, and with the progress of high-speed printing technique, a huge amount of print data is transferred from a host computer. To bitmap this huge amount of print data in a buffer of the printer, conventionally, a high-speed CPU has been employed, otherwise, the unit of data to be handled or the unit of transfer data has been increased (for example, from 8 bits to 16 or 32 bits), otherwise, a hardware dedicated to DMA processing has been employed for data transfer, thus realizing high-speed data processing.
However, in the above conventional techniques, if the transfer bus width is widened to perform high-speed processing by using the hardware dedicated to DMA transfer, the bus width of a CPU bus is also widened in correspondence with the transfer bus width. In this case, the wide CPU bus is used even in data transfer between the CPU and a ROM storing control programs, in which the amount of data is not so large as that of print data transfer and therefore such wide bus width is not required. This means that the data transfer bus for access to the ROM is enhanced, and as a result, the cost of manufacture of a controller increases.