We need specific hardware has to be developed using ref. design, what are the steps involved in HW design?

Hire an engineer.

John

There are a few different ways to slice this problem. I'll take a stab at it. Hopefully others will chime in on things I've missed or whatever.

1) First, if possible, obtain the original schematic and layout and any other design documents if possible. 2) Enumerate functionality changes that are required and or desired. You guys should be able to take a first stab at this part, but you may want to bring in an experienced hardware person to keep you bounded and to think of important stuff you might overlook. For example, it is important to capture all applicable requirements, such as board form factor, agency listings or approvals you will need, operating environment, and so on. Also, you have to work out how you are going to program any programmable parts (FPGA's, ROM's and so on). That is, are you going to program the parts before the board is assembled, or after? If after, you have to make sure you have a plan for how to do it that is electrically sound. Testability needs to be captured here, too. 3) Use the enumerated functionality changes to create a modified schematic. In parallel with this, you should order samples of all the parts to make sure you can get them. Nothing is more frustrating than designing a complicated project around a part which can't be got in time to meet your prototype schedule. This will also allow you to double catch certain layout related errors. 4) When the schematic is done or nearly done, you can create a routing requirements document. 5) Then you place the parts on the board (this is a CAD operation, not a physical operation). Then you route the board according to the restrictions (again, this is a CAD operation) in the routing requirements document. 6) When the design is all routed, you can send the board data to a board house and get boards made. Then you have to have somebody assemble the board (i.e., solder in all the parts). You may have to supply this somebody with programmed parts. You will certainly need to supply this person with information about part locations and a BOM. You may need to provide additional over-riding instructions to NOT install some programmable parts if you plan to install them yourself, after programming them. 7) Then you have to do board bring-up and design validation. Then the board will probably be ready for the software guys. Depending on the details, the software guys may have to be intimately involved in the bring-up. 8) There are a lot of testing and quality control details to be decided upon. This depends on how many boards you will make and who will do the testing, and so on. Some of this may need to be discussed back in step 2. 9) Once the design is thoroughly validated, you can release to manufacturing and move on. If problems are encountered, you may have to go back to repeat steps 3-9 again.

--Mac

There's a great deal to making a prototype design even based on a ref. design. I would agree with John that your simplest route would be hire a hardware engineer.

There's a number of reasons for that, but one of them is because it's a non-trivial design and there's far more to it than merely connectivity between units. Layout (especially in a router) needs a great deal of attention, and that's something learned (generally the hard way.... ;) Note that although it's CAD, a high speed design needs direct involvement from the hardware engineer - layout artists can be great, but I can't expect them to be electrical engineers, and there's a

*huge* number of potential pitfalls for any non-trivial design.

So advertise :)

Cheers

PeteS

This is not a trivial task. Why do you guys want/need to make the changes?

Have you looked at just buying a "newer" unit and modifying the software?

--- Dave