This project is a controller for DCC accessory devices on a model railway that is operated using an NCE DCC control system.
It is based on a PICAXE 20X2 which performs the following functions:
1. communicates with the NCE DCC control system via its RS485 based Cab-bus,
2. scans the 4x4 keypad for User inputs/selections,
3. displays prompts and user inputs on the 16x2 LCD (operating in 4-bit mode),
4. sends the user commands encoded to the NCE Cab keypress codes to the NCE DCC command station.
As an independent device separate from the standard NCE Cab/Throttles, it allows the User to control their model railway DCC accessory devices without switching back and forth between loco control and accessory control making changes possible while maintaining full control over operating locomotives.
The program utilises approximately 2 kBytes of the available 4 kBytes of program memory so there is ample remaining program space for end-Users to make further extensions to the program. There are also 3 remaining IO pins for end-Users further hardware requirements. Other than a MAX485 transceiver chip, the PICAXE 20X2 is the sole IC performing all interfacing and IO actions.
Background information, PICAXE program basics, constructional details, photographs of the internals and front, and the PICAXE 20X2 program code are provided on the PICAXE forum.