On Tue, 20 Jan 2004, der Mouse wrote: Well here is what I would do: Use 34C86 line receivers as inputs - these also have the advantage of having hysteresis and meeting the low input current at 0 VCC spec. You do get about 20 ns of propagation delay but that should be ok. There are faster parts available if need be. The - inputs of the line receivers would be connected to the desired threshold. For drivers, I would use small (SOT23) discrete Mosfets perhaps with a small (10 Ohm?) drain resistor to avoid damage if inadvertantly shorted to 5V. The gate drive could be RC slew limited to keep the output edge rate within reason. For the bus state machine logic, I would use a small FPGA say a XC2S50E-TQ144 (~$12 is low quantities) This would also have enough BlockRAM to present 1KX16 to the QBUS as a boot ROM (is this enough?) and also 1KX16 to the local processor for booting. I would use a standard serial flash for downloading the FPGA config and firmware storage. A 8Mbit serial flash costs about $2.25. Most of this space is free so the local processor can load its RAM from the serial flash (about 900K bytes available) for its MSCP code. For as local processor I would probably use a AMD AU1500 (about $26 for the slowest speed grade, IIRC has serial port, AC97 codec interface for audio, 2 100BT Ethernet, 2 USB ports, SDRAM interface for say 16M SDRAM (about $6.00) and PCI bus. The PCI bus would connect to the IDE controller chip (not sure which to use and price) and perhaps have an expansion slot or two (MiniPCI-3 perhaps - they are low enough to fit) We pay about $.35 per square inch for 4 layer PCBs so with gold I would guess PCB would be in the ~$20.00 range. Peter Wallace