Newbie Question #1

Discussion in 'Embedded Systems and Microcontrollers' started by ttiwkram, May 15, 2012.

  1. ttiwkram

    Thread Starter New Member

    May 15, 2012
    Hi -

    I've read that certain parameters for the PIC16F84 chip, including the oscillator configuration, are set by blowing "fuses" during programming -- which sounds awfully permanent.

    Once the chip has been programmed with the "XT" option, does that preclude it from being reprogrammed as "HS"?

  2. nigelwright7557

    AAC Fanatic!

    May 10, 2008
    The chip is a flash chip so you can reprogram all of it many times.
    ttiwkram likes this.
  3. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    How old are these things you are reading?

    The configuration word hasn't been called "fuses" in a double decade, or since the 90's when they really were fuses.

    Dey be flash now baby.
  4. John P

    AAC Fanatic!

    Oct 14, 2008
    People do still use the word "fuses" but the right term is "configuration word".

    Another thing people keep using even though they shouldn't, is the PIC16F84. It's obsolete, and there are equivalent processors that do more and cost less. But it's easy money for Microchip to keep churning them out as long as there's a market.
  5. maxpower097

    Well-Known Member

    Feb 20, 2009
    Thats what I was thinking but I wasn't sure. I imagined the only think you can't come back from would be a code protect, but I'm not sure if you can erase the chip with that. I just always read people saying they killed their chip by accidentelly having the code protect bit set.
  6. nerdegutta


    Dec 15, 2009
    You can erase the chip, even though the Code protection is set. But you cannot read the code from a Code protect. It prevents reverse engineering.
  7. ttiwkram

    Thread Starter New Member

    May 15, 2012
    Thanks to all for your responses!

    My info sources have all been on-line, so it's not as if I've been using a 20-year-old textbook or something. :D I guess maybe old terminology just dies hard.

    The chip design is pretty long in the tooth, but I had a couple sitting on the shelf from a few years back so I thought I'd use them. I figure they're good for learning and practicing. This will be the first chip I've ever programmed; right now I'm just working through the "fits and starts" phase. You know -- nailing down the hardware connections, switch and software settings, etc. Once I get the first one to work, I figure most of my future designs will use identical or similar setups.