I’m a bit confused on the interface to this module. I want to put logic level DCC in and get 14v DCC out to drive a model train decoder. So I guess I want to use it as an ‘amplifier’ more than a motor controller? Has anyone done this? How did you wire it?
Hello.
We are not very familiar with digital command control (DCC) signalling, but it seems possible that the MC33926 could work like that. Page 17 of the MC33926 datasheet has a truth table that shows the state of the driver’s outputs given different inputs and some figures that illustrate some of those states. If you alternate between the “Forward” and “Freewheeling Low” device states by toggling IN1 logic-high and then logic-low, OUT1 will alternate between VIN and GND and OUT2 will always be connected to GND.
You might want to look more carefully at the “Dynamic Electrical Characteristics” section of the datasheet to see if the fidelity of the DCC signal will be preserved. Does your system use the 58µs/100µs timing indicated on that DCC wiki page?
-Nathan
Yes, my code adheres to the DCC standard. It’s an interrupt driven state machine. I have it working with the LMD18200, however with the price of that chip being $16 or so and your MC33926 carrier being only $2 more with about the same current capability, I would prefer a finished device as a driver. Thanks very much for the link to the truth table, I had missed that. I will do some research this weekend. I am also evaluating the VNH5019 for powering DCC for large scale (G) locomotives as it can source 12A (nice!). I will post my findings here, thanks again for the info.
Got this configuration to work today. I am driving an Economi 200 DCC decoder with a 14.8v Lipo. Xbee supplies the packet to the microcontroller, it generates the DCC stream on the fly.
Top is the input, bottom is the output. This was done with 5v rather than the 14v but it shows the output matches the input. (Note- the label on the lower channel should be OUT2)
Excellent. I am glad to hear it is working. Thanks for sharing your results here.
-Nathan