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HELP! no response from propeller — Parallax Forums

HELP! no response from propeller

lyons5959lyons5959 Posts: 13
edited 2007-02-23 17:28 in Propeller 1
I have checked schematics and actual wiring of board more than twice now, but I can't get any response from my propeller. I'm using a propplug to program, which verifies for ram but throws an error when verifing for eeprom. I know all of the connections are right but I can't even get a simple pin test program to toggle some pins. I have used a 5.00MHz crystal on all PLL settings and have also used RCFAST and RCSLOW. I have two chips and neither work. All power supplies are good with VDD at 3.27V. another problem is that none of the crystals that I have produce any output whatsoever. Whats the deal, did I just get a bad set of chips?

Michael

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2007-02-23 04:31
    If you can download to RAM, the Propeller itself is working, at least with the built-in RCFAST clock. If it can't verify writing to EEPROM, that means that either the EEPROM is not wired correctly or is defective. It's very unlikely that more than one chip is bad in the same way and more likely that there is, in fact, a wiring error of some kind. It may be that you have a defective crystal. If you don't have the proper measurement equipment, you won't be able to test the crystal for output. It's fairly low level and sensitive to capacitive and resistive loading.

    It might be helpful for you to post your schematic and your simple test program.
  • Graham StablerGraham Stabler Posts: 2,507
    edited 2007-02-23 12:42
    When checking the circuit be sure to use a multimeter to go from pin to pin checking continuity, it is amazing the number of times that something looks to be connected (because there is a piece of wire between the points) when in fact it is not. Reasons are many and varied including hairline breaks in tracks, dry joints, bad connections in breadboards, broken multicore cable, cruddy chip sockets.......

    Graham
  • Paul BakerPaul Baker Posts: 6,351
    edited 2007-02-23 17:28
    The chips are very robust, I have zapped them, I have coursed 1.5Watts of power through them and I have yet to completely destroy a chip and Ive only been able to fry an I/O pin or two. Post your schematic and we will look at it, I have destroyed an EEPROM and the system exhibited the same problem you are reporting, so it may be that.

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    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
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