| 摘要 |
PURPOSE: A method for communication between multiple sub systems is disclosed to effectively process the communication between each boards by using dual port RAM and interrupt. CONSTITUTION: A method for communication between multiple sub systems is composed of request, transmission, and confirmation. Master board's CPU stores outgoing data designated for slave board in main memory(S01), requests for data transfer to dual-port RAM controller(DPRAMC)(S02), which constantly checks for transfer requests(S03). If there is transfer request, DPRAMC enables B_INT# signal(S04), checks BUS_IDLE# state(S05), and when enabled, reserve communication bus by disabling BUD_IDLE#(S06). When bus is free, DPRAMC enables B_INT# and interrupt controller(IC) requests for interrupt to CPU by enabling IRQ#(S07). CPU stops other commands and accepts request(S08). IC turns off bus trash interrupt mask, disables B_INT# signal(S09) until transmission request, executes bus trash interrupt. CPU transmits data(S10), enables slave board's L_INT#, sends transmission completion address(S11). DPRAMC checks for transmission completion and when completion address is recognized, BUS_IDLE# signal is disabled and it waits request signals(S12).
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