JDM programmer

Discussion in 'Embedded Systems and Microcontrollers' started by msdagiya, Apr 21, 2012.

  1. msdagiya

    Thread Starter New Member

    Apr 21, 2012
    hi Guys,

    I have a question. I designed a JDM programmer from OLIMEX website for PIC microcontrollers. However, It is not in working conditin. I used ICProg and PICpgm to program the PIC16F877A but unfortunatly none of these software detect the PIC. I thought that poor soldering could be a reason. However I checked all my connections and my soldering was good. I also cheked by Vdd and it shows 5Volts on it. my PGM and Vss pins are both at 0Volts. and my LED is glowing as well when programmingg. I also checked clock and data pins and both these pins show around 2.5V on digital multimeter. my MCLR pin has also 13Volts on it. It seems that all my circuitry is done well. But still boht programs ICProg and PICpgm gives error on programming hte device. Can som one please help me with this, I am completly stuck and dont know what to do.

  2. BillO

    Distinguished Member

    Nov 24, 2008
    Your voltages sound right. It may be the way you have things connected, either to the PIC or to the serial cable.

    Is the PIC in-circuit, or is the only thing attached to it the JDM?
  3. panic mode

    Senior Member

    Oct 10, 2011
    there is a big problem with JDM programmers - they only work on SOME serial ports.
    in particular USB-RS232 converters score bad because they are unable to provide required power. main problem is the 13V programming voltage, if this is too low (less than 12V) then chip is not programmed. some people ended simply redesigning the programmers so that +13V is obtained from pair of 9V batteries connected in series (and then regulated down to 13V), some use external power supply. but ones that try to steal power from RS232 are ones that have bad reputation because more often than not, they fall flat on their face.

    here is generic JDM circuit:


    the 13V programming voltage is expected to be across C2 (clamped down to 13.3V by D6 and D2 which are in series).

    note that for JDM requires use of handshaking lines. using 3-wire RS232 cable is another way to make this not work.

    but your circuit seem to manage those 13V and that is good. next thing you need to do is use proper settings in programming software. for example ICprog has details on how to set JDM programmer.

    go to http://www.ic-prog.com/index1.htm and click on "Settings for official supported programmers". JDM is on top.
  4. msdagiya

    Thread Starter New Member

    Apr 21, 2012
    Thanks for reply. I found the problem this morning.. I mistakenly connectied both data and clock pins. so it worls now:) Thanks agian for the reply