Mains Track power DCC signal missing?

PaulS Aug 5, 2016

  1. PaulS

    PaulS TrainBoard Member

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    Hello, I'm new to DCC++ (with a bit of DCC and Arduino knowledge). I've set up an Arduino Uno with Arduino motor shield and have been able to communicate with the Arduino via the Arduino IDE's serial monitor and JMRI (ie turn on/off Programming track power, read/write CV's). With a scope I can see the DCC bi-polar 15V pulses on the Programming Track but I am unable to see the DCC signal on the Mains Operation track (ie ChB has both lights on, whereas ChA has only one LED on). Also, pin 10 on the Arduino is fixed at 5V (lifted jumper 11-12 and measured on pin 11). Is there something special that needs to be done to get the Mains track output working ? Any help/ideas on this would be greatly appreciated.

    Thanks in advance,
    Paul
     
    Scott Eric Catalano likes this.
  2. Scott Eric Catalano

    Scott Eric Catalano TrainBoard Member

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    If it was a pololu shield I could be of help....does seem like a pin mapping or a trace cut that needs to be done....as both outputs need to have....in my case...both red and green lights to be on
     
  3. Atani

    Atani TrainBoard Member

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  4. Jirka

    Jirka TrainBoard Member

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    Hi, I do not understand which jumper you mention at pin 11?
    In case you have jumpers as Atani recommends and it does not help, you should test pin 10 of the shield and of Arduino against short circuit (probably against pin 11).
     
    Scott Eric Catalano likes this.
  5. PaulS

    PaulS TrainBoard Member

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    Thanks for the prompt replies Scott, Atani and Jirka. I'm using the Arduino Motor Shield (with the Vin and Brake jumpers cut on the back). Both ChA and ChB work with the programming track (ie PWM output 5 on the Arduino), but there is no PWM output on pin 10 (measured with scope at pin 10). I've now tried the Processing Master Contoller, able to turn track power off/on, but still no signal from output 5 of the Arduino. I guess my next step would be to try a test program to see if output 5 (pwm OC0B) actually works...? Any other ideas would be greatly appreciated.

    Paul
     
    Scott Eric Catalano likes this.
  6. Scott Eric Catalano

    Scott Eric Catalano TrainBoard Member

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    Before I started to assemble my DCC++ board I first made sure both pf the PWM channels worked using a regular DC locomotive....if both channels worked on DC then I know that both would work via DCC++ and I would have to double check my pin mappings and trace cuts...which on the Pololu shield the PWM did use different mappings and Gregg figured it out for me. There are different variations of motor shields out that and some of the traces and pin mappings aren't standard.
     
    sboyer2 likes this.
  7. PaulS

    PaulS TrainBoard Member

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    Hello All, I should have realized the Arduino pin 10 output (16 on the ATmega328 chip) was not working (output toggling between 4.5 and 5V, not 0 - 5V as would be expected). Replaced the chip, programmed it, and all works well now, ... onto making a throttle ...

    Cregg, you're work on DCC++ is fantastic, looking forward to working with this system.

    Paul
     
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