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Did I fry my Gadget Gangster platform? — Parallax Forums

Did I fry my Gadget Gangster platform?

MicrocontrolledMicrocontrolled Posts: 2,461
edited 2010-12-15 18:36 in General Discussion
Hi,

For the upcoming Student LED challenge, I have made a large countdown display using 14-segment LED displays. There are 8 characters in total, and they are controlled by 2 shift registers. However, after wiring them up, the program I wrote ran for about 30 seconds then stopped, now the Propeller tool can't see a Propeller chip. The regulators, EEPROM, and Prop chip were very hot. The shift registers should have sank enough current, as these are low power displays, but is it possible the Prop died from being overloaded? The prop plug still works, and the lights on the board still power on.

Comments

  • hover1hover1 Posts: 1,929
    edited 2010-12-15 12:09
    Micro,

    You are quite the seasoned forum person, and I'm sure you know that you really need to post a schematic and code to have it looked over.

    Your description could mean any of a dozen things went wrong.

    Let's look at the docs and lend a hand.

    Jim
    Microcontrolled wrote: »
    Hi,

    For the upcoming Student LED challenge, I have made a large countdown display using 14-segment LED displays. There are 8 characters in total, and they are controlled by 2 shift registers. However, after wiring them up, the program I wrote ran for about 30 seconds then stopped, now the Propeller tool can't see a Propeller chip. The regulators, EEPROM, and Prop chip were very hot. The shift registers should have sank enough current, as these are low power displays, but is it possible the Prop died from being overloaded? The prop plug still works, and the lights on the board still power on.
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2010-12-15 12:54
    @hover1: Yea, I know better by now, I was just in a rush. Attached are the pictures of the setup, no schematics availible as of now, but this is the Shift Register connection: 
                    
                      ┌──────┐
                  QB  ┫1•  16┣  Vcc                 
                  QC  ┫2   15┣  QA                                
                  QD  ┫3   14┣─────────────────────────────── ← A (Data in from Propeller)              
                  QE  ┫4   13┣─────────────────────• Output Enable (Ground each one)            
                  QF  ┫5   12┣───────────────┐     ← Latch Clock         
                  QG  ┫6   11┣─────────────┐ │     ← Shift Clock 
                  QH  ┫7   10┣──────────────────┐  ← RESET 
                 gnd  ┫7    9┣───────┐ QH' │ │  │
                      └──────┘       │     │ │  │    Notes:
                                     │     │ │  │    • Propeller feeds data into "A" input of first stage.
                      ┌──────┐       │     │ │  │    • QH' from first stage feeds into A of next stage
                  QB  ┫1•  16┣  Vcc  │     │ │  │    • Tie all RESET, Latch Clock and Shift Clock pins together    
                  QC  ┫2   15┣  QA   │     │ │  │    • QA - QH are data outputs: Vcc = 1, gnd = 0                  
                  QD  ┫3   14┣───────┘ A   │ │  │             
                  QE  ┫4   13┣─────────────│─│──│───•  Output Enable (Ground each output enable)               
                  QF  ┫5   12┣─────────────│─┻──│───•  Latch Clock (to LatchPin from Propeller)                 
                  QG  ┫6   11┣─────────────┻────│───•  Shift Clock (to ClockPin from Propeller)
                  QH  ┫7   10┣──────────────────┻───•  RESET (to Vcc or to Propeller's Reset pin)
                 gnd  ┫7    9┣───────┐ Qh'
                      └──────┘       │
                                    to next 74HC595 Data in (pin 14)
                                     or leave disconnected if last one

    DSC00515.jpg
    DSC00514.jpg
    DSC00513.jpg
    DSC00515.jpg
    1024 x 768 - 110K
    DSC00514.jpg
    1024 x 768 - 81K
    DSC00513.jpg
    1024 x 768 - 125K
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2010-12-15 12:56
    Code attached
    spin
    spin
    ShiftRegister7segObject v.1.1.spin
    2K
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2010-12-15 12:59
    Are you running the 595's at 5V? If so do you have any resistors between the Propeller pins and the 595's?

    Luckily the chips are in sockets so if the Prop is toast you can easily swap it out.

    Robert
  • hover1hover1 Posts: 1,929
    edited 2010-12-15 13:14
    @Robert,

    That is the first thing I thought, but the Propeller is pretty tolerant of output to 5V devices rather than input.

    @Micro

    Grounds tied together?

    Jim
    RobotWorkshop wrote: »
    Are you running the 595's at 5V? If so do you have any resistors between the Propeller pins and the 595's?

    Luckily the chips are in sockets so if the Prop is toast you can easily swap it out.

    Robert
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2010-12-15 13:15
    I'd still prefer my prop NOT to be toast, but I think it's inevitable. I've found the cause, I connected the power common of the last display one pin to the right, directly short circuiting it every time it pulses in the multiplex. Now the question is, can I revive the Propeller?
  • hover1hover1 Posts: 1,929
    edited 2010-12-15 13:20
    Can you revive burnt wood?

    Sorry, bad parallel.

    Jim
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2010-12-15 14:31
    Point taken. I didn't figure there was one anyway. I'll swap it out with a new one and try again.
  • $WMc%$WMc% Posts: 1,884
    edited 2010-12-15 18:36
    Just think of all the board space and money we could save with-out the need for current limiting resisters!....stupid resisters !!!
    '
    A friend of mine at work,(not in the elc. field) Asked me for a couple of fuses. I gave him a box of 10. He returned about 30 minutes later and asked me if I had another box of fuses. I asked him what happened to the first box I gave him? He replied that they were all bad, since every fuse he put in blew every time he tried to run the small pump he was working on.
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