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  • Lock-outs

    I know this has been discussed before but I've never heard this sequence of events prior to being locked out of a device before.
    I've been happily programming the same 16LF1823 probably about 20 times on my board. I was investigating using a 16F1823 for another project, so I wanted to check and see if the 'F' version existed in my not so updated Micro Code studio lists of devices.
    I had the program open in Micro Code Studio that I had been playing with for the LF version I had been programming.
    So I found the 'F' version and closed down for the night.
    This morning I went to program the 'LF' version and got th dreaded "Target Device does not match selected device" and realized I hadn't change the 'F' back to the 'LF'.
    So I changed it back to 'LF' and that's when I got the error and keep getting it.
    Tried 'low voltage erase', reluctant to try 'Determine Target Device'

  • #2
    Test by clicking Program > Get Target Information.

    If it always reports 0000 or 3FFF, then the programmer isn't communicating at all with the chip. No settings other than device selection will have any effect if this is the case.

    I don't know if this normally causes a lockout. The major difference when selecting the F vs LF is the voltage output on the Vdd pin of the programming header (pin-4). If you're not using this pin to power your board, the effect is negated.
    Charles Leo
    ME Labs, Inc.
    http://melabs.com

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    • #3
      No not powering with programmers Vdd. Says 'target device I.D. is 2829'. And 'Target device matches selected device. I did get it to program using 'low voltage erase' just now but I'm not powering the chip at all.

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      • #4
        When you View Target Information the ID matches, but when you program you get "Target Device does not match selected device"? Is this correct?

        If so, it's new to me. It's not the standard lock-out problem because you can put it into programming mode to read the target id. Something takes it out of programming mode once programming starts.

        The chip has to have power in order to program. Sometimes it will power from the Vpp signal, but if you're programming in-circuit it would have to power your whole board, depending on the circuit.

        Charles Leo
        ME Labs, Inc.
        http://melabs.com

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        • #5
          Correct, if I power the device and program I get "Target Device does not Match Selected Device" in normal 'erase mode'. If I don't power the device and use 'Low Voltage Erase mode' I can in circuit program (only power at this point on the board would go to the PIC and as you suggested, I assumed it was getting it's power from the Vpp) and it programs. Once programmed, I power it normally and use one pin to trigger a servo that has it's own regulated power, and it does what the program is supposed to (a test moving the servo back and forth repeatedly) and here the PIC is getting power from a 3.3V regulator off a main battery supply (the same supply I tried to use to program it in normal 'Erase Mode'.

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          • #6
            I have no explanation for this.
            Charles Leo
            ME Labs, Inc.
            http://melabs.com

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