Under construction!
current status: just ideas!

DCC Decoder Tool

    This software allows for the evaluation and optimisation of decoder parameter, like Kp, Ki and Kd of BEMK-Decoders. The rotational speed of the motor is measured (in short intervals). This measurement is triggered by the corresponding DCC command, thus the step response of the regulator could be determined.
    Command List Decodertool (Speed-o-meter)
    C<num> change configuration, see packet analyzer 
    TM<num> Set trigger mode. This setting defines how a measurement is started.
    0Mode manual: Everytime a trigger command (T) is received, a measurement is performed.
    1Set trigger to external. An event (i.e. activation of the Optocoupler (== falling edge on the processor pin)) starts a measurement.
    2Set trigger to 'locomotive command'. The next DCC locomotive command starts the measurement. If a dedicated locomotive is configured, only commands to the dedicated address will start the measurement.
    3Set trigger to 'locomotive command' & 'different speed'. If a dedicated locomotive is configured, only speed changes on the dedicated address will start the measurement.
    A Adjust measurement level
    no parameter supplied: do an auto adjust. This requires that the whole system under test (locomotive, IR sensor and reflector) must be prepared and revoluting. The software will now search for a sense level which allows for the measurement of the rotational speed.
    parameter: set compare level to this value.
    This command will return the measured level.
    F<num> Format
    0: standard, readable format
    1: logview compatible format
    I<num> Set Measurement Interval, unit 1ms
    If more than one measurement is performed (speed vs. time plot), this value sets the sample rate. If a measurement isn't terminated inside one interval, it will get a value of 0
    S<num> Measurement vector length, default = 1
    This value sets the number of measurements performed after a trigger, a vector of comma separated values with the length S will be returned. Default is 1 (only one measurement), maximum is 128
    L<num> Select locomotive for triggering  
    TTrigger a measurement. The answer is an array of numbers.100;121;143;

Background information on speed measurements

    The measurement uses the internal 16 bit counter in capture mode. The counter runs with internal clock, there are dividers for 8, 64 256 and 1024. Giving a crystal frequency of 16MHz, the resolution of the timer is 500ns, 2.5µs, 16µs or 64µs.
    64µs resolution is used here. The counter will overflow after 4.19s, therefore the minimum detectable speed is 14rpm. On the other end, the resolution is fine enough to measure 10000rpm with an accuracy of 1%.