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Richard Erlacher
11/11/05 00:04
Read: 855 times
Denver, Co
USA


 
#103562 - It's probably at least fast enough ...
Responding to: Craig Steiner's previous message
The DS89C4x0 types are probably plenty fast enough for your application, since they generate one instruction cycle for each clock cycle, unlike the "old" 805x types that divide the clock by 12, or the Atmel parts that divide the clock by 4, or even the other Maxim/Dallas parts of which some divide the clock by 3. These guys have 1Kb of on-board SRAM, in addition to the standard 128 bytes, and they can map it such that it resides in either program or data memory. Further, they contain 16, 32, or 64KB of FLASH, which (except on the 89C420) can be programmed "on-the-fly." They can, under software control, change the rate at which the core divides down the clock, thereby reducing speed/power product, and they can do lots of other things not common to the 80C3xx, 80C4xx, or other parts of Dallas origin. All these guys have two data pointers, so moving things around in memory is pretty easy, AND the memory map can be quite flexibly fiddled with under software control.

They also have some external memory addressing capabilities, called paged addressing, which saves a clock tick in accessing external memory. All this is not particularly interesting if you don't have performance-critical tasks to perform, but if you do, you can see whether they can help you.

I've not fiddled with other than the 89C420 from this series, but, the sheets seem to suggest that the 89C450, with 64KB of internal FLASH, can access that 64KB as well as an external 64KB, AND an external 64KB of data memory/peripheral space as well, and that's all on a standard 8052 DIP-40 or PLCC-44 footprint. With the aid of a small CPLD to latch/buffer the addresses and data, all the page modes are available. Those can also be used with a bus switch or the like, but a fast, small, cheap CPLD is nearly fast enough to allow you to use those modes without having to program (under software control) additional external bus-cycle time, so you can run at maximum warp.

RE

List of 67 messages in thread
TopicAuthorDate
8051 8-bit computer      Jeff Corr      10/19/05 06:09      
   (or z80)      Jeff Corr      10/19/05 06:10      
   8051 computer      Craig Steiner      10/19/05 08:05      
      I never cringe on a "fun exercise" I do,      Erik Malund      10/19/05 08:21      
         awesome?      Jeff Corr      10/19/05 11:09      
            Computer      Craig Steiner      10/19/05 11:45      
               8051 Computer.      Arif Deshmukh      10/19/05 11:57      
               Minor corrections      Craig Steiner      10/19/05 20:31      
                  11MHz?      Jan Waclawek      10/20/05 00:59      
                     Not sure      Craig Steiner      10/20/05 08:07      
                        Congratulations      José Félix Díaz Ivorra      10/20/05 11:25      
                           Actually it's teh same        Craig Steiner      10/20/05 12:38      
                        11MHz      Phillip M Gallo      10/20/05 11:33      
                        Re: 8051 computer      Valentin Angelovski      10/20/05 18:37      
                           Just us      Craig Steiner      10/20/05 21:12      
                              Project Team      Sriharsha Vedurmudi      10/21/05 00:42      
                                 me tried      Oleg Sergeev      10/21/05 01:13      
                                    thoughts on project      Jeff Corr      10/21/05 02:28      
                                       What is a true multitasking controller?      Russell Bull      10/21/05 03:54      
                                          multitasking controller      Jan Waclawek      10/21/05 04:05      
                                             video      Oleg Sergeev      10/21/05 06:30      
                                             continued..      Jeff Corr      10/22/05 19:37      
                                          continued..      Jeff Corr      10/22/05 19:35      
                                             I don't think so      Craig Steiner      10/22/05 20:02      
                                                color display?      Jeff Corr      10/22/05 21:36      
                                                   Predko Video      Phillip M Gallo      10/22/05 23:17      
                                                      yes      Jeff Corr      10/23/05 13:38      
                                                      video, timing, speeds etc.      Jan Waclawek      10/25/05 10:28      
                                                         Video Timing.      Phillip M Gallo      10/25/05 14:36      
                                                            6.2MHz pixel clock?      Jan Waclawek      10/26/05 01:20      
                                                               Pixel Clock      Phillip M Gallo      10/26/05 11:39      
                                                                  pix clock      Phillip M Gallo      10/26/05 15:10      
                                                                  overclocking      Jan Waclawek      10/26/05 15:20      
                                                                     pad pixels      Phillip M Gallo      10/26/05 16:15      
                                                just a suggestion      Erik Malund      10/24/05 11:54      
                                                   Speed      Craig Steiner      10/24/05 13:22      
                                                      DS'4x0      Phillip M Gallo      10/24/05 17:26      
                                                      DIP / surface mount      Jeff Corr      10/24/05 19:32      
                                                         a 100MHz chip in a perf board? methinks      Erik Malund      10/25/05 06:33      
                                                Hardware multitasking      Sasha Jevtic      10/24/05 17:49      
                                                Multitasking redefined      Dan Henry      10/25/05 06:55      
                                             Misplaced self belief...      Donald Catto      10/24/05 03:01      
                                                Daunting?      Andy Neil      10/24/05 04:08      
                                                breadboarded      Jeff Corr      10/24/05 12:05      
                                                   TRS-80      Andy Neil      10/24/05 13:07      
                                                      TRS80?      Jan Waclawek      10/24/05 14:45      
                                                         in the beginning there was ..      Erik Malund      10/24/05 14:52      
                                                         TRS-80 Info      Phillip M Gallo      10/24/05 14:54      
                                                            Man those were the days.      Jon Ledbetter      10/24/05 15:22      
                                                               That fast?      Craig Steiner      10/24/05 16:00      
                                                                  More retroinfo      José Félix Díaz Ivorra      10/24/05 16:49      
                                                                  TRS-80 forward speed.      Phillip M Gallo      10/24/05 17:11      
                                                                  Like I said, It was a long time ago      Jon Ledbetter      10/25/05 07:48      
                                                               hrm      Jeff Corr      10/24/05 19:16      
                                                                  TRS80 model 1 speed...      Rob Vassar      10/24/05 19:47      
                                                         TRS80      Jan Waclawek      10/25/05 07:55      
                                                            You think?      Craig Steiner      10/25/05 08:38      
                                                               OK so both      Jan Waclawek      10/25/05 10:30      
                                                   No pictures yet      Craig Steiner      10/24/05 13:27      
                                                      Video Capture Card?      Jon Ledbetter      10/24/05 13:31      
                                                         Nope      Craig Steiner      10/24/05 13:47      
                                                      video output      Jeff Corr      10/24/05 19:27      
                                                Qui?      Rob Vassar      10/24/05 18:45      
                                                Multitasking      Grant Beattie      10/25/05 10:44      
                                                   Real Time and Multi Tasking      Ian Bell      10/25/05 15:47      
                                             Maybe whomever has "no idea what I'm tal      Erik Malund      10/24/05 11:51      
      It's probably at least fast enough ...      Richard Erlacher      11/11/05 00:04      

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