For requirements beyond the capabilities of the onboard peripherals and QPSI expansion, the CF1 brings out the full CPU bus including programmable chip select lines that eliminate almost all glue logic. The circuit diagramed below is taken from our CF1 IDE hard drive adapter minus the power switching electronics. Four MSI chips are all that's required, not only to create the IDE interface, but to perform the logic level translation from the 3.3 volt CF1 to 5 volt IDE drives.

Most bus expansion tasks will actually be simpler than this example. You can add almost any number of 74LVC245s to create multiple 8-bit or 16-bit input ports, or use 74LPT574s for multiple 8-bit or 16-bit output ports. Most 3.3V LSI peripherals will connect directly to the bus without buffers, and you can copy this scheme to connect 5V parts.

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