RCBus-hard-sector-controller layout

[Norberto Collado]

Based on your experience, when the parts won't fit on the pcb, what actons have you taken to make it work? I could make the board wider to get additional space for layout.

[Mark T]

Can you reduce the chip count? Maybe replace gates with decoders or multiplexers. That looks like a lot of dicrete logic on that layout.

Put some of the components under the ICs, for example the decoupling capacitors or resistors. The capacitors might fit in the gaps between sockets, you don’t want them in a bunch anyway.

Switch to SMT, first the caps and resistors, those are easy to solder smt.

Mark

[Bill Shen]

Mount resistors, capacitors on solder side;  DIP can be mounted on solder side as well.  Mount resistors on ends; SMT components on both sides; 4-layer pc board for more dense routing; partial decode addresses; remove address and data buffers; programmable logic to consolidate logic.

  Bill

[Greg Holdren]

Beating a dead horse here I guess. 

GALs/PALs/CPLDs

Reduce logic if possible

Hide passives under IC sockets and/or place from the back

SMT :)

Other than that stretch the board upwards like you have shown. 

Possibly use a second board with ribbon cable depending on signaling requirements.

I'm developing a Microchip/Microsemi Igloo2 FPGA card and will have to address these concerns with the I/O I'm putting on the board. Probably will be all SMT but will grow board vertical if need be.

Greg

[Norberto Collado]

Thanks for such great feedback.

Norby