1 2 3 Previous Next 79 Replies Latest reply on Nov 26, 2011 8:03 AM by udayan.umapathi

    Custom PSoC 3 Board Design

    kartik.mankad

      Hey guys,I'm an undergrad student from BITS Pilani,Goa campus,heading the on-campus CUA Initiatives.We're trying to build a custom PSoC3 board,to better suit our specific needs and for wider exposure of this tech amongst our student body.

         

      The first version is going to be a bare-bones solution,i.e just the PSoC3 chip,the required capacitors around and a programming header,with as many pins broken out to headers as possible.All power rails will be provided via off-board supplies,or not.Lets see.

         

      A few specs the board needs to meet,( I do understand these might be impossible to meet

         

      1.Single Sided

         

      2.Can be etched using toner-transfer method of self PCB Fabrication.(Hence the first point)

         

      3.Can be hand soldered 

         

      4.Low Cost.

         

      All these point toward the DIY nature of board production and assembly,essential for easy access to PSoC3 solutions,without requiring large numbers of FTKs and DVKs.

         

      Let me discuss each part of that in some more detail,since I want some help on this design.

         

      The PSoC 3 Chip - Owing to the fabrication constraints mentioned above,we're going to go with the 48pin SSOP chips of the PSoC3 family for our initial designs. We would like to go with the CY8C3866PVI-021 (most feature rich SSOP part) but its $14.So,our next option is the CY8C3246PVI-147,which is priced at $7.We do lose a few features,but lets see how that goes.

         

      .

         

      Just the required capacitors - We'll probably have 0805 SMD caps where needed,according to the schematics(I'll come to that) in the datasheet for the PSoC3 Family.

         

      .

         

      Programming Header - Now this is the tricky bit.We would like to reduce cost and parts,hence the mini prog would be the first to go.That leaves us with 2 options,one - build that FX2LP programming circuitry OR,do a one-time program of a custom UART/SPI bootloader. The latter is more attractive,since it goes along nicely with our aims on this board(Simple to build,Cheap and widely useable).I have been following some topics here on the forum in this regard,and hope that this can be implemented.We do have old miniprogs from our PSoC1 kits,Could those be used to burn on the bootloader? ..Or is the new MiniProg3 absolutely necessary for that?

         

      Power - There are lot many power rails than conventional controllers,so each of these will be broken out to a header(on our first fab).Adding some LDO voltage regulators etc will be a plan for the future,since as of now,the aim is to get a basic programmable platform.

         

      .

         

      Schematics - I'm not too sure on how the older MiniProgs(I2C ones..) can be used to program the psoc3,so I'm a little hazy on those details.If someone could clarify the chip's basic requirements with respect to programming etc for this initiative,I'd be greatful.

         

      Comments,suggestions and criticism are most welcome on this.

         

       

         

       

         
        • 1. Re: Custom PSoC 3 Board Design
          kartik.mankad

          Basically need some input on the real-world feasibilty of the above described design.

             

          .

             

          We'll try and have it be prototyping friendly(shields like the arduino,breadboard plugin-able without too much space loss etc) too,but I think thats too many design demands for a day :)

          • 2. Re: Custom PSoC 3 Board Design
            udayan.umapathi

             

               

            Hey guys,I'm an undergrad student from BITS Pilani,Goa campus,heading the on-campus CUA Initiatives.We're trying to build a custom PSoC3 board,to better suit our specific needs and for wider exposure of this tech amongst our student body.

               
                Cool ! Great to see students working with PSoC!   
               
                    
               

            1.Single Sided

            It is possible to make a single sided PCB for PSoC, however it is going to be tough. A doucble sided PCB with very few jumps between the two sides can be designed if carefully done.

            2.Can be etched using toner-transfer method of self PCB Fabrication.(Hence the first point)

                3.Can be hand soldered    

             

            Toner-Transfer method is ideal for student projects - to make a PCBs on your own. There are tutorials on the web that describes how to do a double sided PCB using UV(very similar to toner-transfer method). To design the PCB there are many free PCB design softwares, what I used as a student is Eagle. You can create your own footprint and schematic library for PSoC3 using Eagle. I have created libraries for CY8C3866AXI, TQFP 100 pin package. SSOP is easy to solder(In case you find it difficult to solder, you can learn from Youtube).

            In any PSoC3 board you will find plenty of 0.1uF,1 uF and 10uF capacitors. These capacitors are provided to eleimnate transients(0.1 uF) and to hold charge(Bulk Caps, 1uF and 10uF). If the power supply is gauranteed to be stabilised few of these capacitors can be eliminated. But it is always recommended to provide these capacitors for best performance.

            4.Low Cost.

            Bootloader solution will certainly turn out to be a cheaper solution. Since UART is being phased from PCs, USB will be a better Bootloader solution. 

            With respect to programming SWD programming is the most reliable method of programming and it is supported by Miniprog3 programming. 

            I hope this helps.

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            • 3. Re: Custom PSoC 3 Board Design
              kartik.mankad

              Hey,

                 

              I dont have a lot of experience with fabrication,but I'll manage well,since I am experienced with the design end of it.

                 

              Yes,looks like a single sided board will be difficult to pull off,especially since I want to make it breadboard plugin-able(which means it cant take up lots of space on the board).Anyway,thats a later thing,since I will be prototyping this idea with a breakout board on a breadboard with associated caps and a miniprog to fire in the bootloader.

                 

              As far as the schematics go,I'm drawing them up tonight,and have opened a design review case for the same.

                 

              Only point I still need some clarification is the USB bootloader.There was an appnote, "USBFS Bootloader for PSoC(R) 3 and PSoC 5" which I cant seem to locate presently.

                 

              If the bootloader works out,(by works out I mean,the chip as well as PC side sofrware) then this board can be a really attractive prototyping solution for students and engineers everywhere,since the cost wont exceed Rs.500(USD ~10).While it is by no means a replacement for the awesome FTK/EVKs,but it can definitely make this great chip more accessible.

                 

              As it occured to me the other day,I'm trying to Arduino-ize the PSoC(in terms of hardware...) 

              • 4. Re: Custom PSoC 3 Board Design
                kartik.mankad

                As part of later additions to this design,

                   

                -we could have boards bootloading each other(like the appnote that shows a 5 doing so to a 3),which means you'll need only one miniprog3,for the very first board :)

                   

                -Though USB Bootloading is very attractive not only for the low cost and super short BOM,it does cut out the debug features you'd get via SWD or JTAG.However,theres still USBUART(on board options..else an LCD or any other output peripheral is super easy to use with the PSoC),which is good enough for most projects.

                • 5. Re: Custom PSoC 3 Board Design
                  markus.hoelzl

                  hello

                     

                  i plan to do similar than you, but i am fortunately emplyed to a company, and we should

                     

                  deliver quality electronics to our valued customers which results in 4-Layer FR4 NiAu-plated..

                     

                   

                     

                  but for prototyping a set of DVK 001 is at my hand, but they should not leave the lab.

                     

                  for testing the programmed firmware in real environment off the lab i like to recommend a tiny schmartboard.

                     

                  (www.schmarboard.com modell# 202-0011-01 rev B)

                     

                  the granted me a free sample o a tqfp 32-100 0.5mm pitch board. excellent for

                     

                  handsoldering the "big" PSoC3 parts since improved solderstop mask is on the pcb

                     

                  and lot of pads for mounting 0805 caps on both sides . each pin is outlet to 1/10" raster and fit to drill board.

                     

                  i personal, would not miss my miniProg3 for programming (fast ) and debugging,

                     

                  so the 10pin SMD header is also in my design but from different vendor than DVK part (lot cheaper)

                     

                  if additional electronis should be employed to your project and additional PCB space is need,

                     

                  plug your "DIY processor board" onto your PCB, but strongly recommend double side.

                     

                  even if you can process single side only, make excessive use of the groundplane.

                     

                  ( you may take a look to some older ham-radio  VHF projects, doing so for years..).

                     

                   

                     

                  just a few thoughts concerning about the topic  "building a cheap but well working

                     

                  psoc3 equipment".

                     

                   

                     

                  good luck and greets from germany

                     

                  Markus

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                  • 6. Re: Custom PSoC 3 Board Design
                    kartik.mankad

                    Many thanks for the inputs,markus68.

                       

                    Your post raised another doubt,regarding speed of programming via USB Bootloader.Will need to look into that too..

                       

                    Also,does anyone have a copy of that USB Bootloader appnote? "USBFS Bootloader for PSoC(R) 3 and PSoC 5" , If so,please share the associated code and pdf.

                    • 7. Re: Custom PSoC 3 Board Design
                      kartik.mankad

                      Another thing I just realized is,I will need to go with the CY8C3866PVI-021 part,since the cheaper CY8C3246PVI-147 doesnt have USB! :P

                      • 8. Re: Custom PSoC 3 Board Design
                        udayan.umapathi

                        Attaching the USB Bootloader Example that was originally available on Cypress website. Currently it is being totally revamped and possibly everybody can have a complete USB Bootloader soon(We request your patience until then  ) !  Arduino-ize the PSoC(in terms of hardware...)? Interesting. Probably you can come up with a PSoCduino !

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                        • 9. Re: Custom PSoC 3 Board Design
                          udayan.umapathi

                          Project and document attached now.

                          1 of 1 people found this helpful
                          • 10. Re: Custom PSoC 3 Board Design
                            kartik.mankad
                                    what is the timeline for the final release of the USB Bootloader Appnote?   
                            • 11. Re: Custom PSoC 3 Board Design
                              kartik.mankad

                              Attached is a picture of the (home) etched form of the breakout board for the Cy8C3866PVI-021.

                              • 12. Re: Custom PSoC 3 Board Design
                                kartik.mankad

                                Also attached is the pcb layout in pdf,incase anyone would want to take a shot at etching one for themselves.They are all 8mil tracks.

                                • 13. Re: Custom PSoC 3 Board Design
                                  kartik.mankad

                                  Just for Info,the software used to create this was Fritzing,and not something more professional like eagle or altium,since I'm still working on the creating the Cy8C3866PVI-021 part for them.(which is super easy on Fritzing,since they already have a 48pin part,just need to edit an SVG for the schematic symbol)

                                  • 14. Re: Custom PSoC 3 Board Design
                                    kartik.mankad

                                    Sorry for no updates on this...was busy organizing this semester's PSoC1 Lecture series,and then tests(doing my masters in chemistry) came along(still on).

                                       

                                    Will add more as soon as I get free.

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