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16F877A JDM programmer problem solved

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  • eeiminako
    Thanks for the advice. I previously had to use PICStart to program 16F877A, but adding a 10kohm resistor from RB3 (LVP pin) to GND made it possible to program
    Message 1 of 3 , Dec 1, 2003
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      Thanks for the advice. I previously had to use PICStart to program


      16F877A, but adding a 10kohm resistor from RB3 (LVP pin) to


      GND made it possible to program in-circuit with a JDM programmer


      also.




      Somehow, the resistor was needed EVEN if the LVP configuration


      bit had been all the time disabled (this was why it was so


      hard to figure out the problem...)






      Eei
    • Eur van Andel
      ... It may have been disabled in the program, but it is disabled in the PIC only after successful programming. Does the 877A come with a factory default LVP
      Message 2 of 3 , Dec 1, 2003
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        On Mon, 01 Dec 2003 08:06:32 -0000, "eeiminako" <eeiminako@...> wrote:

        >Somehow, the resistor was needed EVEN if the LVP configuration
        >bit had been all the time disabled (this was why it was so
        >hard to figure out the problem...)
        It may have been disabled in the program, but it is disabled in the PIC only
        after successful programming.

        Does the '877A come with a factory default LVP on?


        --
        Ir. E.E. van Andel, Fine Wire Heat Exchangers, Fiwihex B.V. www.fiwihex.com
        Wierdensestraat 74, NL-7604 BK Almelo, The Netherlands eur@...
        phone +31-546-491106 fax +31-546-491107 mobile +31-653-286573
      • eeiminako
        ... PIC only ... Yes, I think so. Now I took the resistor away and programming is still possible, so it seems the LVP bit was really set all the time. I
        Message 3 of 3 , Dec 1, 2003
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          --- In jallist@yahoogroups.com, Eur van Andel <eur@f...> wrote:


          > On Mon, 01 Dec 2003 08:06:32 -0000, "eeiminako" <eeiminako@y...>
          wrote:


          >


          > >Somehow, the resistor was needed EVEN if the LVP configuration


          > >bit had been all the time disabled (this was why it was so


          > >hard to figure out the problem...)


          > It may have been disabled in the program, but it is disabled in the
          PIC only


          > after successful programming.


          >


          > Does the '877A come with a factory default LVP on?


          >




          Yes, I think so. Now I took the resistor away and programming is still
          possible, so it seems the LVP bit was really set all the time. I
          thought I had tried to set the bit off with PICStart but it seems I
          managed to mess up somewhere :|


          If I recall correctly, I used a 16F877 with faulty (nonlinear) A/D
          module in-circuit in debugging and then ran the final software to the
          16F877A with PICStart. It wasn't much trouble, luckily.




          Eei





          >


          > --


          > Ir. E.E. van Andel, Fine Wire Heat Exchangers, Fiwihex B.V. www.
          fiwihex.com


          > Wierdensestraat 74, NL-7604 BK Almelo, The Netherlands eur@f...


          > phone +31-546-491106 fax +31-546-491107 mobile +31-653-286573
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