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???
01/20/05 21:36
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 		 #85449 - DS89C420 ISP
Responding to: ???'s previous message
Panagiotis Gousis said:
Can you tell me how to connect for example pin 1 of 74ls125 to which pin of max232 or of the 89c430


74LS125 pins 4, 10, and 13 get attached to MAX232 DTR output. Pin 5 gets tied to +5V, pins 9 and 12 get tied to ground. Pin 6 goes to the MCU reset line, pin 8 goes to MCU EA line, pin 11 goes to PSEN line.

If DTR on RS-232 DB9 pin 4 is tied to pin 8 of MAX232, then pins 4, 10 and 13 of 74LS125 should be tied to pin 9 of MAX232.

Be sure that the EA line on the MCU isn't connected directly to +5V since the 74LS125 will be unable to drive it low when DTR is asserted.

Hope this helps.

Regards,
Craig Steiner


List of 34 messages in thread
TopicAuthorDate
Need programmer for DS89C430 & DS80C310            01/01/70 00:00      
   The datasheet for 430 says:            01/01/70 00:00      
   Or use a terminal program            01/01/70 00:00      
   ... or do it the easiest way...            01/01/70 00:00      
      It works fine            01/01/70 00:00      
         Errata!            01/01/70 00:00      
   Does NOT work!!!Help!            01/01/70 00:00      
      Or can you tell me            01/01/70 00:00      
         DS89C420 ISP            01/01/70 00:00      
   Or maybe            01/01/70 00:00      
      I meant crystall at 4 Mh.            01/01/70 00:00      
      NOOOO            01/01/70 00:00      
         Did you look at PCB Layout?            01/01/70 00:00      
            No            01/01/70 00:00      
               I don't understant much            01/01/70 00:00      
   Heelpp!!            01/01/70 00:00      
      bad title, bad link            01/01/70 00:00      
         DS89C4x0 ISP            01/01/70 00:00      
         About the link            01/01/70 00:00      
            Link works here            01/01/70 00:00      
      Link            01/01/70 00:00      
         same place            01/01/70 00:00      
   Link again            01/01/70 00:00      
   Back to the main issue...            01/01/70 00:00      
      No scope,            01/01/70 00:00      
         But this is the FULL circuit diagram            01/01/70 00:00      
            use something else            01/01/70 00:00      
            Oh no it isn't            01/01/70 00:00      
               Look at the bottom            01/01/70 00:00      
                  but..            01/01/70 00:00      
                     Cap on Pin 2 to connected Vcc            01/01/70 00:00      
                        which goes to show.....            01/01/70 00:00      
                           You 're right            01/01/70 00:00      
                              Make a start.            01/01/70 00:00      

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