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9ISA 是 Industry Standard Architecture 的缩写 引脚定义方向说明A1/I/O CH CKI/O channel check; active low=parity errorA2D7Data bit 7A3D6Data bit 6A4D5Data bit 5A5D4Data bit 4A6D3Data bit 3A7D2Data bit 2A8D1Data bit 1A9D0Data bit 0A10I/O CH RDYI/O Channel ready, pulled low to lengthen memory cyclesA11AENAddress enable; active high when DMA controls busA12A19Address bit 19A13A18Address bit 18A14A17Address bit 17A15A16Address bit 16A16A15Address bit 15A17A14Address bit 14A18A13Address bit 13A19A12Address bit 12A20A11Address bit 11A21A10Address bit 10A22A9Address bit 9A23A8Address bit 8A24A7Address bit 7A25A6Address bit 6A26A5Address bit 5A27A4Address bit 4A28A3Address bit 3A29A2Address bit 2A30A1Address bit 1A31A0Address bit 0B1GNDGroundB2RESETActive high to reset or initialize system logicB3+5V+5 VDCB4IRQ2Interrupt Request 2B5-5VDC-5 VDCB6DRQ2DMA Request 2B7-12VDC-12 VDCB8/NOWSNo WaitStateB9+12VDC+12 VDCB10GNDGroundB11/SMEMWSystem Memory WriteB12/SMEMRSystem Memory ReadB13/IOWI/O WriteB14/IORI/O ReadB15/DACK3DMA Acknowledge 3B16DRQ3DMA Request 3B17/DACK1DMA Acknowledge 1B18DRQ1DMA Request 1B19/REFRESHRefreshB20CLOCKSystem Clock (67 ns, 8-8.33 MHz, 50% duty cycle)B21IRQ7Interrupt Request 7B22IRQ6Interrupt Request 6B23IRQ5Interrupt Request 5B24IRQ4Interrupt Request 4B25IRQ3Interrupt Request 3B26/DACK2DMA Acknowledge 2B27T/CTerminal count; pulses high when DMA term. count reachedB28ALEAddress Latch EnableB29+5V+5 VDCB30OSCHigh-speed Clock (70 ns, 14.31818 MHz, 50% duty cycle) B31GNDGroundC1SBHESystem bus high enable (data available on SD8-15)C2LA23Address bit 23C3LA22Address bit 22C4LA21Address bit 21C5LA20Address bit 20C6LA18Address bit 19C7LA17Address bit 18C8LA16Address bit 17C9/MEMRMemory Read (Active on all memory read cycles)C10/MEMWMemory Write (Active on all memory write cycles)C11SD08Data bit 8C12SD09Data bit 9C13SD10Data bit 10C14SD11Data bit 11C15SD12Data bit 12C16SD13Data bit 13C17SD14Data bit 14C18SD15Data bit 15D1/MEMCS16Memory 16-bit chip select (1 wait, 16-bit memory cycle)D2/IOCS16I/O 16-bit chip select (1 wait, 16-bit I/O cycle)D3IRQ10Interrupt Request 10D4IRQ11Interrupt Request 11D5IRQ12Interrupt Request 12D6IRQ15Interrupt Request 15D7IRQ14Interrupt Request 14D8/DACK0DMA Acknowledge 0D9DRQ0DMA Request 0D10/DACK5DMA Acknowledge 5D11DRQ5DMA Request 5D12/DACK6DMA Acknowledge 6D13DRQ6DMA Request 6D14/DACK7DMA Acknowledge 7D15DRQ7DMA Request 7D16+5 VD17/MASTERUsed with DRQ to gain control of systemD18GNDGround
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