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Sasha Jevtic
07/26/05 14:33
Read: 1647 times
Barrington, Il

#98211 - Yes, it's nice
Responding to: Matthias Arndt's previous message
Matthias Arndt said:

I've just partially read the data sheet and user guide for the DS89C450 and stumpled upon this builtin bootloader.
Do I understand it right that no programmer except for a standard Max232 and a serial lead is needed and that one can directly load Intel HEX files with any terminal software into the code memory?

Yes, you're right about the builtin bootloader. You must also force a few pins on the device to enter bootloader execution mode; this is what the 74xx125 tri-state buffers shown in Dallas' documentation are for. And yes, you do just load up standard Intel Hex files over the serial port; the bootloader takes care of all the parsing and decoding for you. It should be possible to do the downloading with standard terminal software. However, if you use standard terminal software, be sure to pay attention to the responses from the device to ensure that your programming is succeeding as expected. Still, there are not a whole lot of reasons to use standard terminal software when freely available special-purpose programming utilities for these devices exist, such as Dallas' MTK and my own 89C4x0ldr-lite, unless you are on an unsupported platform. The former offers a user-friendly GUI, while the latter offers a simple, scriptable CLI.

If that is really the case than this should be the device of choice for students and hobbyists IMHO.


Well, it's a nice device. If you can run it at moderate frequencies, it's quite manageable, and can still outperform a lot of more conventional 8051-based devices. But, as you head for the upper range of clock speeds, you start running into issues. An LS address latch is no longer sufficient. Stretch cycles become necessary to interface with many peripherals. Noise shows up on ALE. And the list goes on.

Note that none of this is to say the device is inappropriate for students and hobbyists, but I think it would be a daunting challenge for a first expierience with microcontrollers without someone providing a good amount of hand-holding.

--Sasha Jevtic

List of 38 messages in thread
Looking for 80C251 board      Henry Sodens      07/25/05 21:20      
   DS89C450 is fast 8051.      Charles Bannister      07/25/05 22:34      
      Cheap 'n' cheerful      Russell Bull      07/26/05 01:56      
      builtin bootloader      Matthias Arndt      07/26/05 03:05      
         Common place        Steve M. Taylor      07/26/05 05:06      
            good to know      Matthias Arndt      07/26/05 06:45      
               And Texas Instruments        Craig Steiner      07/26/05 06:58      
                  DS89C4x0      Jan Waclawek      07/26/05 07:19      
                     Not sure      Craig Steiner      07/26/05 07:35      
                        DS89C420 vs. DS89C430/440/450      Sasha Jevtic      07/26/05 14:45      
                     You are probably right      Matthias Arndt      07/26/05 09:53      
                  ok      Matthias Arndt      07/26/05 09:55      
            Death of the Programmer        Andy Neil      08/01/05 02:21      
         Yes, it's nice      Sasha Jevtic      07/26/05 14:33      
            comments      Erik Malund      07/26/05 14:42      
      "marketing"      Erik Malund      07/26/05 07:26      
         let's put it this way:      Jan Waclawek      07/26/05 07:46      
            Which is exactly what they say ...      Phillip M Gallo      07/26/05 13:00      
               overview      Jan Waclawek      07/26/05 14:55      
                  DS'420 IAP      Phillip M Gallo      07/26/05 15:03      
                     I'm not polite...      Jan Waclawek      07/26/05 15:31      
                        MAXIM/Dallas and Flash      Phillip M Gallo      07/26/05 16:16      
                           common practice today      Erik Malund      07/26/05 16:23      
                           Nor forgetting      Steve M. Taylor      07/27/05 07:42      
                              DS2250 - Secure Micro      Phillip M Gallo      07/27/05 11:57      
      Very nice and informative      Kai Klaas      07/30/05 05:19      
   Saved a few cents for a lot of work.      Charles Bannister      07/26/05 02:42      
      In-system programming      Sasha Jevtic      07/26/05 14:59      
         ISP Header        Phillip M Gallo      07/30/05 11:31      
      schematics?      Christian Kleiber      07/28/05 00:08      
         if you are looking for schematics of ISP      Erik Malund      07/28/05 05:59      
   Why on earth      Erik Malund      07/26/05 06:30      
   '251 board      Phillip M Gallo      07/26/05 13:10      
   if you decide to leave the '51 (which yo      Erik Malund      07/26/05 13:19 SBC supports DS89C420      Jon Ledbetter      07/27/05 15:23      
   Dead Thread?      Andy Neil      08/01/05 05:03      
NOTICE: Message(s) moved      Craig Steiner      07/30/05 08:40      
   Moving posts      Terry Lingle      07/30/05 10:27      

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