Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
08/10/06 22:49
Read: times


 		 #122005 - Home made JTAG
Responding to: ???'s previous message
Hi Tercio,

When I entered this forum I was having the same problem, and it can be somewhat hard to solve...

Certainly the best option would be the one suggested by Erik: buy an ATMEL programmer. But if you are willing to build your own JTAG anyway, maybe this link can help:

http://www.8052.com/forum/read.phtml?id=120785

If you follow it message by message, you will find some schematics and the solution I came up with.

Currently I'm using the JTAG that can be found here:

http://www.8052.com/forum/read.phtml?id=120811

with a 74F244 buffer. I'm programming using the AT89ISP software.
(This circuit has the pin assignments compatible with ATMEL's program, but it's not guaranteed to work because the buffer should be signal compatible to your computer LPT port - this can be TTL or CMOS - and should also be compatible with the microcontroller).
You can try other buffers, like 74LS244 (TTL) or 74HC244 (CMOS), to test if something works.

It seems that the best option would be to implement this circuit:

http://www.8052.com/forum/read.phtml?id=120836

I didn't test it yet, but will do soon.

I would advice you to buy an ATMEL ISP cable too, as I had a lot of headache with this... but if you still want to try a home made one...

Good luck!

Leonardo.

List of 53 messages in thread
TopicAuthorDate
AT89s52 error with programmers            01/01/70 00:00      
   the 'weekly' question get the weekly answer            01/01/70 00:00      
   Add some pull up resistors (4.7K\'s) on LS device.            01/01/70 00:00      
      risque business            01/01/70 00:00      
   Home made JTAG            01/01/70 00:00      
      It is so refreshing to see thing like this instead            01/01/70 00:00      
         Tested!            01/01/70 00:00      
            have you 'tested' that the flash caps are fully            01/01/70 00:00      
               Atmel does that            01/01/70 00:00      
                  I think you are wrong            01/01/70 00:00      
                     I don't think so            01/01/70 00:00      
                        yes, and no            01/01/70 00:00      
                           Bah, shoot that designer :-)            01/01/70 00:00      
                              not the chip designer            01/01/70 00:00      
                                 JTAG x Flash Data Retention            01/01/70 00:00      
                                    nope            01/01/70 00:00      
   Tnx for answers...!            01/01/70 00:00      
   89s52 programmer            01/01/70 00:00      
      Only LS chips            01/01/70 00:00      
         there is the mail            01/01/70 00:00      
            here is world´s end            01/01/70 00:00      
               However far it from nowhere, I am sure you have ma            01/01/70 00:00      
                  You can buy here!            01/01/70 00:00      
                     he can do it himself...            01/01/70 00:00      
            What more fast than 9 ns?!            01/01/70 00:00      
               I do not understand. What I said is not to find s            01/01/70 00:00      
         Then stop doing in electronics!            01/01/70 00:00      
   re: AT89S52 error            01/01/70 00:00      
   Somebody test buffer CD4010?            01/01/70 00:00      
      the CD40 is sloooooooow compared to HC            01/01/70 00:00      
         What more fast than 9 ns?!            01/01/70 00:00      
            Not the speed is reason only            01/01/70 00:00      
   But and the pull ups in buffer´s out?            01/01/70 00:00      
      Does that suggest anything to you?            01/01/70 00:00      
      Type "74VHC244" into the search window            01/01/70 00:00      
         show the calculations            01/01/70 00:00      
      Schematic of programmer using 74LS244            01/01/70 00:00      
         Circuit that i am using            01/01/70 00:00      
            the very reason            01/01/70 00:00      
               Right...!            01/01/70 00:00      
                  have you conmsidered a 'radical' approach            01/01/70 00:00      
                     RX2...?!            01/01/70 00:00      
                        Rx2            01/01/70 00:00      
            Try this one            01/01/70 00:00      
               a full circle            01/01/70 00:00      
                  Time for a decision...            01/01/70 00:00      
               I did it...!            01/01/70 00:00      
                  Can\'t you order the parts by mail?            01/01/70 00:00      
      the old STUPID "It is tested"            01/01/70 00:00      
         Gee, another BS answer from Erik.            01/01/70 00:00      
            I can BE QUITE specific about what I post            01/01/70 00:00      
         "tested" does not mean tested            01/01/70 00:00      
            and even then ...            01/01/70 00:00      

Back to Subject List