| 摘要 |
<p>A page printer with an internal CPU (15), interrupt controller (9), and direct memory access controller (DMAC) (18) has a direct memory access (DMA) stopping circuit (18a) in the DMAC, the function of which is to stop DMA transfer in response to a DMA stop signal and restart it in response to a DMA restart signal. The DMA stop signal is generated by the interrupt controller (9) when it selects certain interrupt requests, such as communication interrupt requests, enabling the CPU (15) to service these requests promptly. The DMA restart signal is generated at the end of the interrupt service routine. This arrangement permits DMA transfers to be performed in burst mode, stopping only when urgent interrupt service is required. Burst-mode DMA improves the speed of operation of the printer.</p> |
