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JDM programmer won't program PIC18F26K22

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Synaps3

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I am trying to use a JDM programmer to program a PIC18F26K22 (that's a 5V enabled one). The problem is I'm getting "Verify failed at address 0000h" using PICpgm. I see this problem posted many times, but it's from people building their own programmers. I bought this programmer AND IT WORKED ON A PIC16F before on the same computer (don't remember the exact model). So what is the problem with this chip? I checked LVP is disabled. I tried reading back the program and it's all zeros, so it's not actually being programmed at all.
 

andre_teprom

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Are you interfacing with JDM programmer through native COM serial port from your computer, or some kind of USB adapter ?
 

Synaps3

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Native COM serial with no adapters or cables.
 

Synaps3

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Do you mean config bits when you say "fuses"? I tried to set all the code protection config bits to disabled, but it won't program them.
 

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You are probably already aware that JDM circuit topology has some issues concerning to the (non)reliability of its internal conversion of RS232/TTL standard voltage levels.

As an attempt to minimise this as a potential cause of the problem, you could check if the brown-out-reset "configuration bits" of the 18F are defined to the most sensitive option, what supposedly could make the uC fall into a reset state in ocurrence of the lower voltage drop during programing process.
 

Synaps3

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The brown out reset is set to 2.85V when I try to "read" it, but I think the program is just loading defaults because it can't read. In my hex it is set to the lowest voltage, but it doesn't matter because it won't program. Do you think it is likely I will get this working or do I need to buy a better programmer?
 

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Do you think it is likely I will get this working or do I need to buy a better programmer?
Hard to say without precisely determine whether the problem is with your chip or with your serial port levels. My own experience with this programmer was not so good, but some persons do not face any problem, so this could vary from case to case.

Sometimes I dealt with write errors with no apparent reason, even without physically handling the circuit, due was writing directly via ICSP connector.
 

Synaps3

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What pins can I measure to verify the correct programming voltages?
 

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I would recommend firstly check the 5V bus, during programing.
Do you have an Oscilloscope ?
 

Synaps3

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Yes, I have an oscilloscope and I will check that.

PS: When do I not have to be approved? :)
 

Synaps3

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desktop or laptop ?
Desktop.

I put an oscilloscope on the JDM pins, but I was unable to detect anything. I think it's because I can't seem to force the software to program the JDM when the slot is empty and if I put the PIC in, it's basically impossible to keep the oscilloscope in the slot and it's too hard to put the wires directly into the serial connector.

Any last thoughts? I think Im going to buy the pickit 3. (I need this for a project not just messing around, so I need a quick solution.)
 

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You must to also consider the possibility to have a problem with this device in particular. Are there another spares for ensure that the problem can be related to the programmer, not the chip itself ?

Anyway, to have an extra programmer would not be at all an useless decision; I have many. At the next time, you can use it to eliminate the programmer as the cause of the problem.
 

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it tells you that you must program this chip with max 9v for vpp, so use LVP is mandatory.
did you try to program it using LVP ?
No, I didn't. The JDM is 12V, right?

I got the Pickit 3 and it programs it at 5V with no problems, so the chip appears to have not been damaged.
 

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