| 摘要 |
PURPOSE:To reduce the load of a processor and to shorten transmitting time by transferring a character pattern from a font memory to a front buffer by a DMA and transmitting the character pattern to a printer simultaneously with the transmission from the memory to the buffer. CONSTITUTION:When a character pattern in the font memory 4b built in a printer controller 13 is transferred to the font buffer 6, a control signal 9 for starting DMA transfer is sent from the processor 1 to a DMA controller 8b. Receiving the signal 9, the controller 8b actuates address and data buses, transfers a character pattern in a program memory 3 to the buffer 6 and informs the end of transfer to the processor 1 through the control signal 9. The buffer 6 consisting of the 1st and 2nd font buffers 6a, 6b transfers the character pattern to a printer device 6 simultaneously with the transfer of the character pattern from the memory 4b to the buffer through DMA. Consequently, the load of the processor 1 is reduced and the transfer time is shorten. |
