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???
10/08/07 20:49
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#145521 - the rough picture
Responding to: ???'s previous message
OK so I produced a rough diagram of the whole "design" (obviously a lot of things are missing, for example all of the SFRs, and also a lot of things are simply hidden in the boxes...).

I am almost sure I will "steal" Richard's "design" of ALU - i.e. I am not going to dig deeper than "it adds and subtracts and similar stuff".

I was trying to draw a couple of those unreadable "timing" "diagrams" about the CALLs and RET and it turns out that there are many ways to do things... And I can't simply decide which way to go, as I don't know the "relative cost" of each approach (which btw. must be also technology-dependent, i.e. one solution is more suitable for implementation in FPGAs whereas other might be better for raw silicon...). For example, I could imagine a separate INC/DEC unit for SP incrementing/decrementing, or, the ALU can be "recycled" for the same task; the question is, what are the costs and benefits of both options in terms of gate number and speed...

JW


List of 282 messages in thread
TopicAuthorDate
Let's make a '51!            01/01/70 00:00      
   ???            01/01/70 00:00      
      Maybe yes...            01/01/70 00:00      
         Still digging!            01/01/70 00:00      
            re above            01/01/70 00:00      
               digging deep            01/01/70 00:00      
                  It depends on your goal            01/01/70 00:00      
         Thanks            01/01/70 00:00      
   a simulation which actualy works            01/01/70 00:00      
      clockwise            01/01/70 00:00      
      Not Nesasarily            01/01/70 00:00      
   WHAT?            01/01/70 00:00      
      Yeah, C...            01/01/70 00:00      
   From reading the subject title...            01/01/70 00:00      
      verilog to c            01/01/70 00:00      
         FpgaC            01/01/70 00:00      
            there are more similar            01/01/70 00:00      
            re :FpgaC            01/01/70 00:00      
               it's just as with any other C...            01/01/70 00:00      
   Step1: Program Counter, code fetching...            01/01/70 00:00      
      finite state machine            01/01/70 00:00      
      Step 1 1/4: the byte counter&some more infrastruct            01/01/70 00:00      
         Step 1 1/2: first problems            01/01/70 00:00      
            Why not do this ...            01/01/70 00:00      
               reset in a dozen of ways            01/01/70 00:00      
                  It\'s really simple and stupid            01/01/70 00:00      
                     Faking out the LJMP            01/01/70 00:00      
                        You can't have it both ways ...            01/01/70 00:00      
               To IOR or not to IOR            01/01/70 00:00      
                  it's probably a logic reduction            01/01/70 00:00      
                     TRANSPARENT latch?            01/01/70 00:00      
                        Using clocked registers requires multiple clocks            01/01/70 00:00      
                        How to build an oscillator            01/01/70 00:00      
                           it's simple, but not THAT simple            01/01/70 00:00      
                              Where does the IOR belong in my picture?            01/01/70 00:00      
                                 You've got to have a complete picture.            01/01/70 00:00      
                                    Thanks            01/01/70 00:00      
                                       much depends on how you perceive it            01/01/70 00:00      
                     To IOR or not to IOR            01/01/70 00:00      
                        By all means, let\'s see what you think should work            01/01/70 00:00      
                           I don\'t know how I would do it            01/01/70 00:00      
                              Why do you think it\'s a lot of logic?            01/01/70 00:00      
                                 maybe later I will arrive to the LJMP            01/01/70 00:00      
                                    It is only one of a number of options.            01/01/70 00:00      
                  to reset or not to reset            01/01/70 00:00      
                     Not so fast, there, Pilgrim ...            01/01/70 00:00      
      Is there a picture?            01/01/70 00:00      
   Simulator            01/01/70 00:00      
      well, maybe...            01/01/70 00:00      
         The question is one of what you\'re simulating            01/01/70 00:00      
   Opportunity            01/01/70 00:00      
      How about this?            01/01/70 00:00      
         Thaks            01/01/70 00:00      
      not this time...            01/01/70 00:00      
         VHDL vs C            01/01/70 00:00      
            Where you sit (and when) determines what you see            01/01/70 00:00      
               ABEL is now available free            01/01/70 00:00      
               VHDL verbosity            01/01/70 00:00      
                  Entering everything more than once is not safety            01/01/70 00:00      
                  That\'s exactly what it is!            01/01/70 00:00      
                  on tools etc.            01/01/70 00:00      
                     You could, of course, use schematics ...            01/01/70 00:00      
   some basics from the wikiwhatever            01/01/70 00:00      
      Caution is indicated            01/01/70 00:00      
   What's your goal?            01/01/70 00:00      
   Step 2: The ticks counter (and the promised bonus)            01/01/70 00:00      
      BOTTOM-UP vs TOP-DOWN DESIGN            01/01/70 00:00      
   I am stuck            01/01/70 00:00      
      Prototype the ALU?            01/01/70 00:00      
         it's still hard            01/01/70 00:00      
            Jan, if you like \"bottom-up\" ...            01/01/70 00:00      
               I\'ve added a simulation            01/01/70 00:00      
      Maybe you should complete the design            01/01/70 00:00      
   step 2 1/2: MOVCs and JMP @A+DPTR            01/01/70 00:00      
      Design, then implement???            01/01/70 00:00      
         the gross picture            01/01/70 00:00      
            To the C hater            01/01/70 00:00      
               pictures and amusement            01/01/70 00:00      
                  it\'s probably not as amusing ...            01/01/70 00:00      
                     hummmm....            01/01/70 00:00      
                        that is what you have to explore            01/01/70 00:00      
                  ...and this isn\'t very amusing either            01/01/70 00:00      
      Well, this is YOUR game ...            01/01/70 00:00      
         the simplest way            01/01/70 00:00      
            ... there are many ways...            01/01/70 00:00      
               indeed, there are many ways ... BUT ...            01/01/70 00:00      
               re: there are many ways            01/01/70 00:00      
               re: microcoded MCU's            01/01/70 00:00      
                  not really microcoding...            01/01/70 00:00      
                     where there's a will ...            01/01/70 00:00      
                     constraints            01/01/70 00:00      
                        yes, but there's certainly a lower bound...            01/01/70 00:00      
                           lower bound?            01/01/70 00:00      
                              achievable minimum            01/01/70 00:00      
                           lower bound?            01/01/70 00:00      
                              perhaps what he means is a minimal delay            01/01/70 00:00      
   the rough picture            01/01/70 00:00      
      Now, this is YOUR project ... but ...            01/01/70 00:00      
         this is what I am talking about - relative cost            01/01/70 00:00      
            try to benefit from prior art            01/01/70 00:00      
         sorry - double post            01/01/70 00:00      
      I like the new picture            01/01/70 00:00      
         it's ugly            01/01/70 00:00      
            There is no requirement for beautiful drawings            01/01/70 00:00      
            Just sketch and scan ...            01/01/70 00:00      
               Early drawings should be ugly and disorganized.            01/01/70 00:00      
                  I'm not just being contrary, BUT ...            01/01/70 00:00      
                     maybe this is the way how a stupid programmer...            01/01/70 00:00      
                        Too much emphasis on art, not enough on science            01/01/70 00:00      
                     You ARE contrary, but we love you anyway.            01/01/70 00:00      
               is this simulation of this circuit?            01/01/70 00:00      
                  YES!            01/01/70 00:00      
               correction?            01/01/70 00:00      
                  there are certainly 254            01/01/70 00:00      
                     I may be reading something incorrectly            01/01/70 00:00      
                        whoops, double post again, sorry            01/01/70 00:00      
                        try mine            01/01/70 00:00      
                           did you notice the redundant opcodes?            01/01/70 00:00      
            If you like, you can use PAINT!            01/01/70 00:00      
               GIF            01/01/70 00:00      
                  this is not available as a default option...            01/01/70 00:00      
   detour - QR6, and how to explain my ideas...            01/01/70 00:00      
      ???            01/01/70 00:00      
         read one-by-one...            01/01/70 00:00      
            Too late!            01/01/70 00:00      
      Why the context switch?            01/01/70 00:00      
         simplicity            01/01/70 00:00      
            They're unrelated            01/01/70 00:00      
               sure they are unrelated....            01/01/70 00:00      
                  Maybe it\'s just grapho-semantics            01/01/70 00:00      
                  I'm a little confused            01/01/70 00:00      
                     this is not meant to be useful...            01/01/70 00:00      
                     Now I see!            01/01/70 00:00      
                        What's next?            01/01/70 00:00      
      MHO            01/01/70 00:00      
         Correction            01/01/70 00:00      
      One thing I missed ...            01/01/70 00:00      
         yes, and...            01/01/70 00:00      
            pre-ANSI K&R            01/01/70 00:00      
               yes, thanks            01/01/70 00:00      
            Here\'s the K&R chapter            01/01/70 00:00      
   Let\'s make a \'51 core            01/01/70 00:00      
      I like it...            01/01/70 00:00      
         The diagrams are now updated            01/01/70 00:00      
            I thought this is the case...            01/01/70 00:00      
               Bit ops, duplicated registers, and PSW            01/01/70 00:00      
                  I\'d not push SFR into \"internal memory\" at all            01/01/70 00:00      
                     Maybe yes, maybe no            01/01/70 00:00      
                        Certainly no.            01/01/70 00:00      
                           No, certainly            01/01/70 00:00      
                  careful now!            01/01/70 00:00      
                     OT: will there be cheap FPGAs?            01/01/70 00:00      
                        Check ther prices!            01/01/70 00:00      
                           the cost...            01/01/70 00:00      
                              Distributed over the cost of trillions of IC's            01/01/70 00:00      
                     Size vs. Performance            01/01/70 00:00      
                        I think you should do it your way ...            01/01/70 00:00      
                           Bad assumption on my part???            01/01/70 00:00      
                              this is how we see a RAM            01/01/70 00:00      
                                 by way of clarification            01/01/70 00:00      
                              keep instruction set and its implementation apart            01/01/70 00:00      
                                 ???            01/01/70 00:00      
                                    I see what you mean            01/01/70 00:00      
                                       I've almost got it now            01/01/70 00:00      
                                          dunno            01/01/70 00:00      
                                             Dedicated RAM vs flip-flops for SFRs            01/01/70 00:00      
                                          It should have a purpose, should it not?            01/01/70 00:00      
                                             '51 registers R2-R7 are no different...            01/01/70 00:00      
                                                BUT ... he referred only to R0 and R1 ...            01/01/70 00:00      
                                                It\'s all in the approach            01/01/70 00:00      
                                             It does have a purpose            01/01/70 00:00      
                                          Correction            01/01/70 00:00      
                                             I don't think it's impossible...            01/01/70 00:00      
                                                FPGA RAMs            01/01/70 00:00      
                                                   I think I understand that...            01/01/70 00:00      
                                                      It is probably not so easy            01/01/70 00:00      
                                                      bit-split the BRAM            01/01/70 00:00      
                           I think this horse is finally dead            01/01/70 00:00      
                              Be careful not to fool yourself            01/01/70 00:00      
                                 Nobody is fooling anybody            01/01/70 00:00      
                                    Not exactly what I was after, but helpful            01/01/70 00:00      
                                       Out of curiosity, what were you after?            01/01/70 00:00      
                                          I want to understand your approach            01/01/70 00:00      
                                    I try to keep an open mind ...            01/01/70 00:00      
                              dead horses couldn't drag me away            01/01/70 00:00      
                                 A ewe's my aunt            01/01/70 00:00      
                                    You can force the structure to be what you want            01/01/70 00:00      
                                       schematics vs HDL, round 666            01/01/70 00:00      
                                          It's about the money.            01/01/70 00:00      
                                       schematic entry            01/01/70 00:00      
      You may be surprised at how easy it is            01/01/70 00:00      
         It doesn't look too difficult yet ...            01/01/70 00:00      
            different strokes for different folks            01/01/70 00:00      
      Oops - duplicate post            01/01/70 00:00      
   My two cents .. How about Duo/Quad core 8051            01/01/70 00:00      
      Not as simple as that            01/01/70 00:00      
         Just a thought            01/01/70 00:00      
            Exactly!            01/01/70 00:00      
         It's like using a team to do a job            01/01/70 00:00      
            more troubles with multiprocessor...            01/01/70 00:00      
               8051 multi-cores            01/01/70 00:00      
                  Writing code for them would be "interesting" too            01/01/70 00:00      
                  Isn't a '51 core too expensive for this?            01/01/70 00:00      
                     \'multicore\'            01/01/70 00:00      
                        it all depends on the application            01/01/70 00:00      
                           this is not pantyhose            01/01/70 00:00      
                              sure...            01/01/70 00:00      
                     Cost of an 8051 core            01/01/70 00:00      
                        that sounds like pretty expensive to me...            01/01/70 00:00      
               efficiency will surely increase            01/01/70 00:00      
                  How can that be?            01/01/70 00:00      
                     How can that be?            01/01/70 00:00      
                     maybe not "more efficient"            01/01/70 00:00      
                        it might be clever to use a different architecture            01/01/70 00:00      
                           it always MAY be            01/01/70 00:00      
      there are other ways...            01/01/70 00:00      
      One task per CPU is good            01/01/70 00:00      
         you nailed it Russ            01/01/70 00:00      
         that is where things tend fo fall apart            01/01/70 00:00      
   New subtopic - How to initialize block RAM?            01/01/70 00:00      
      there once was a ROM primitive            01/01/70 00:00      
      Initializing BRAMs            01/01/70 00:00      
         re: Initializing BRAMs            01/01/70 00:00      
            re: Initializing RAMs            01/01/70 00:00      
   Update: How the execution unit works            01/01/70 00:00      
   Yet another Verilog question            01/01/70 00:00      
      Yet another Verilog answer            01/01/70 00:00      
         Yet another Verilog thanks            01/01/70 00:00      
            why ... ?            01/01/70 00:00      
   Yo! --- Andy ---- about those fast-carry muxes ...            01/01/70 00:00      
      fast-carry muxes            01/01/70 00:00      
         It's not that simple ...            01/01/70 00:00      
            well ... i don't know.            01/01/70 00:00      
               It depends on what they can do ...            01/01/70 00:00      
                  Now I'm confused.            01/01/70 00:00      
                     it\'s just a documentation issue            01/01/70 00:00      
   Update: Implementation is underway            01/01/70 00:00      
   Update: How to handle C, AC, and OV flags?            01/01/70 00:00      
      there are a couple of ways ...            01/01/70 00:00      
         Can you be more specific?            01/01/70 00:00      
            What I think about your project doesn't matter            01/01/70 00:00      
               Re: what you think doesn't matter            01/01/70 00:00      
                  Now ... please don\'t take this as personal ...            01/01/70 00:00      
                     Okay            01/01/70 00:00      
               if you insist on using schematic entry            01/01/70 00:00      
                  If only it were that simple            01/01/70 00:00      
      you can do it "symptomatically"... but I wouldn't            01/01/70 00:00      
         More on the flags            01/01/70 00:00      
            wrong place ... sorry!            01/01/70 00:00      
      Very ungracefully            01/01/70 00:00      
      Historically...            01/01/70 00:00      
         The key, IMHO, is in the number of data paths            01/01/70 00:00      
            ... or ...            01/01/70 00:00      
               in low production, maybe            01/01/70 00:00      
                  this depends on approach            01/01/70 00:00      
               uC prototyping using FPGAs            01/01/70 00:00      
                  what challenge?            01/01/70 00:00      
         re: Historically            01/01/70 00:00      
            the REAL learning is in what synthesis tools do            01/01/70 00:00      
               Indeed            01/01/70 00:00      
                  xilinx synthesiser and others            01/01/70 00:00      
                  tedium ... yes, that's what it is ...            01/01/70 00:00      
   Update - the core now runs on the FPGA            01/01/70 00:00      
      How much code space does it support?            01/01/70 00:00      
         Re: How much code space does it support?            01/01/70 00:00      
            How about a testbench?            01/01/70 00:00      
               Good ideas            01/01/70 00:00      
            some ideas            01/01/70 00:00      
               Please clarify            01/01/70 00:00      
                  make it vonNeumann...            01/01/70 00:00      
                     I still don\'t get it            01/01/70 00:00      
                        let's not complicate things            01/01/70 00:00      
                           Re: let's not complicate things            01/01/70 00:00      
                              I'm not sure why you'd want to do that ...            01/01/70 00:00      
                              a way how to leave problems to somebody else            01/01/70 00:00      
                                 Von Neumann            01/01/70 00:00      
                              test code            01/01/70 00:00      
                                 Thanks            01/01/70 00:00      
                        Thanks ... it\\\'s clear now            01/01/70 00:00      
      8501 self tests            01/01/70 00:00      
      Another (minor) update            01/01/70 00:00      
         you need external bus            01/01/70 00:00      

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