| 摘要 |
PURPOSE:To obtain a quick and inexpensive communication control system by transmitting continuously data existing separately at different locations via a system bus as a constituting element of one packet. CONSTITUTION:A processor 8 sets a lock register 14 and turns on a lock signal to a bus interface BIF section 7 when an LSI10' for controlling a low-order layer in a communication control unit CCU4 transmits a buffer address in a local memory 9 and a user message in a system memory 2 as one packet to a communication cable 6. The processor 8 transmits the presence of transmission request to the LSI10' and an attention circuit 15. When the circuit 15 is set, a system bus 5 is ready to use to lock the use of the bus 5. When the LSI10' gives an address to a local bus 12, an address register 13 recognizes it, opens a gate of a memory 9 for a buffer address to connect the bus 12 to a bus 5 via a BIF7 to the user message, and the LSI10' accesses the memory 2 to constitute a packet by reading the content from each memory. |
