ladybug Posted January 4, 2003 Report Share Posted January 4, 2003 (well now i m in the "troubles" section :-[ )i've built the jdm on a protoboard and used a 8.2v zener, and the capacitors are of 25v !BUT THE DAMN THING IS NOT WORKING !my tests show :- "enable mclr" = 6.4v- "enable vcc" = 4.7v- "enable clock" = 0v (?!)- "enable data out" = 4.3vi tried it on 3 diferent COMs, its all the same.the i/o delay dont have ANY influence at all.please P-L-I-Z HELP Quote Link to comment Share on other sites More sharing options...
Guest sstandfast Posted January 5, 2003 Report Share Posted January 5, 2003 Hey,The first thing I would check is to make sure all of your connections are solid. I learned this on my attempt to build the JDM. The second thing that I would check is to make sure that the diodes are in the right way. (i.e. is the anode/cathode orientation the way it is supposed to be?)You said that you are using an 8v2 zenner are you sure that this is in properly (facing the right way) and working correctly? To check to see if it is regulating voltage like it is supposed to, run the 'Enable MCLR' test in IC-Prog then measure the voltage from GROUND and verify that it is regulating at 8v2. You can also do this with your 5v1 but from your voltages it looks like it is.Remember, always check the simplest things first as they account for 90% of all design errors. Hope this helps. Keep us updated on your progress.Good Luck!Shawn Quote Link to comment Share on other sites More sharing options...
ladybug Posted January 5, 2003 Author Report Share Posted January 5, 2003 i've found a strange thing :when i put my "-" probe on the #5 (GND) and the "+" probe on #7 (RTS) my friendly multimeter shouts : -5.5 !this means the current is inverted !!and this means..that my #5 is my "+" and the others ( #3,#4,#7,#8 ) are my "-"is this the way it suppose to be ? my (little) knowledge in electronics tells me it is INVERTED. Quote Link to comment Share on other sites More sharing options...
Guest sstandfast Posted January 6, 2003 Report Share Posted January 6, 2003 [glow=red,2,300]when i put my "-" probe on the #5 (GND) and the "+" probe on #7 (RTS) my friendly multimeter shouts : -5.5 ! this means the current is inverted !! [/glow] Yes it does. This is how the serial port works. When data is transmitted serially, some lines are taken 'high' meaning that they reach a "+" voltage with respect to ground while other lines reach "-" voltage with respect to ground. This is how the computer registers a logic one or zero, by the polarity of the voltage on the line with respect to ground.Are you familiar with how the JDM programmer is supposed to work? In order to program PICmicro's using HVP (High Voltage Programming) the voltage on the MCLR pin has to be taken to +13V with respect to Vss in order to trigger 'programming mode' on the chip. Now this is where some understanding of how the RS-232 port or serial port works comes into play. Like I said before, some lines on the serial port can be taken to a '-' voltage with respect to ground. On most new PC's the serial port can swing between -12V and +12V, if this were the case then the programmer would be very simple to build. However, on some of the older machines, the serial port could only swing between -8V and +8V, clearly not enough to trigger programming on the chip. Therefore, the JDM has been built to cater to the lower voltage RS-232 ports.So how does the JDM work? The first thing to remember is that voltage is relitave. What this means is that say we were to take one line on the serial port 'high' or +8V with respect to ground and we were to also take another line 'low' or -8V with respect to ground. If we were to do this that means that there would be a 16v difference between the two lines! More than enough to trigger programming on the chip. And since there doesn't have to be any current flowing between Vss and MCLR to trigger programming we can now use the serial port to program our PIC's.For more information on how the RS-232 port works or for an excellent discription of how the JDM programmer is supposed to work you can visit these links below:RS-232 information:http://www.beyondlogic.org/serial/serial.htmJDM information: http://www.poptronics.com/interactive/FreeProjects/MultiChipPgmr/MultiChipPgmr-P1.htmlHope this helps to clairify some stuff for you. Good Luck!Shawn Quote Link to comment Share on other sites More sharing options...
ladybug Posted January 6, 2003 Author Report Share Posted January 6, 2003 PAFFFF !detz some inside information, when i'll have the time i'll go deep in there...right now i just want it working as fast...here are my results :- "Enable MCLR" = on- my "+" probe on the GND(i m looking on the JDM circuit that is on the "ucapps.de")- on D1 "-" (the side with the | ) i get 5.6v  same on D2 "+"- on D2 "-" i get 0v !!- on D1 "+" i get 4.8v- on D6 "+" i get 4.8v- on D6 "-" i get 0v !!- on D5 "+" i get 0v !!- on D5 "-" i get -1.6vWHAT IS WRONG ??H E L P :'( Quote Link to comment Share on other sites More sharing options...
Guest sstandfast Posted January 9, 2003 Report Share Posted January 9, 2003 Hey,Still no luck I take it. Well from the information you have given it is pretty simple to isolate the general area in which your problem arises from. With respect to ground it sounds like all of your voltages that you have given across the diodes are correct. On the pins where you measured a 0V differential this is because of electrical commonality, they are electrically common so therefore there would not be a voltage drop across those pins. The only place where I saw a problem was on what you call the "-" end or the cathode end of diode D5, the 8v7 zenner. You say that you measured a -1.6V w/ respect to ground and the "+" probe on ground? Well, with the "+" probe on GND and the other one on the cathode end of D5 you should be measuring approx. 8v7 (or 8v2 if you used an 8v2 zenner). If you measure from this side (the "-" end) of D5 to Vss (pin 12/31) do you get somewhere around +/- 5V? If so it sounds like your problem lies somewhere between TXD (DB9 pin 3) and the circuit. This is because the 8V from TXD is somehow not making it to the circuit. I would also bet that there is not a good connection between the actual pin on the connector and the board. Check to make sure that TXD (DB9 pin 3) is making a good, solid soldier connection with the circuit. I would bet that that is exactally what your problem is.If however, the connection checks out, even after resoldering, then I would look to the other diodes, D3 and D4 although it sounds like they are working as well. If the diodes check out, meaning they still limit the direction of current flow, then you might check the transistor Q1. Pull if from the circuit and test it using a transistor tester. If you don't have a transistor checker take an Ohm meter and measure from the base to the collector and the emmiter and check for continuity, it will be small but you should be able to see it. Try it with both leads, pos. and neg. on the base. if it checks out ok then report back and I'll have some more questions for you.Hope this helps to isolate your problem a little bit more for you. Keep us updated on your progress.Good Luck!Shawn Quote Link to comment Share on other sites More sharing options...
ladybug Posted January 10, 2003 Author Report Share Posted January 10, 2003 weird things going on !!first - thank you for all the help !!trying to narrow the problematic area, those are my measurments :- enable mclr is on - disconnecting from D4 i get 11.9v from GND to #3,so far so goodwhen i solder it back on i get from the same point 2.1v !! (a discent bad-word should b here)- D4 is good - checked and replaced on its "-" i get 2.1v, on its "+" i get 1.6v- on Q1 i get 1.6v on both C and E ,on B i get 2.1- on D3 "-" i get 2.1v, on its "+" i get -4.7veverything with respect to GND, the "-" on it.(are we having any progress at all ?) Quote Link to comment Share on other sites More sharing options...
ladybug Posted January 15, 2003 Author Report Share Posted January 15, 2003 i disconnected the BC547C and checked it with a multimeter that got a "transistor-checkin-socket".my result was "012" !does this mean good or bad news ?? Quote Link to comment Share on other sites More sharing options...
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