RTB_C12

My homebrew RTB C12 Micro Booster implements a booster, DCC generator and Real-time Railcom detector. The booster is optimized for N-scale in respect to track voltage and current.

See also

• RTB_C10 - Master
• RTB_C11 - Power
• RTB_C13 - Track Sensor
• RTB_P15 - Base

User Guides

• User Guide - DE
• User Guide - EN

Booster features

• FDX
  • FDX bus (2Mbps full duplex)
• DCC protocol generator
  • unlimited decoder stack depth
  • DCC bandwidth monitor
  • DCC-A protocol (incl. stretched start bit)
  • DCC-R protocol (incl. update of RTB decoder on main)
• MDU protocol generator
  • Zimo MDU (Multi Decoder Update)
  • update of MS and MN decoder
  • can update multiple MN/MS decoder concurrently
• DECUP protocol generator
  • Zimo DECUP (Decoder Update)
  • update of MX decoder
• Doehler & Haass update-protocol generator
  • update of D&H decoder
• Booster
  • Software programmable output voltage (3..18V)
  • 1A continuous current (1.5A peak)
  • Current limiter
  • Short circuit detection
  • Configurable bridge dead time (170ns..3500ns)
  • DCC signal timing adjustable [micro sec granularity]
  • Railcom Cutout timing adjustable
  • Up to 500kHz fast signaling
  • Voltage and current measurement
• Railcom Detector
  • channel 1 / channel 2
  • detects unlimited number of decoder
  • Railcom polarity detection
  • Railcom timing capture for decoder analysis
• Service Mode
  • read/write DCC decoder in “service mode”
  • ACK current detector adjustable
• Firmware update over the bus

Hardware

The PCB layout uses SMD footprints with 0.4mm pitch and mostly 0603 parts. Reflow soldering is recommended, but with some experience handsoldering is also possible. Further, the PCB has been optimized for automated assembly (BOM and Position files as CSV).

PCB

• 4-layer PCB, FR4, 1.6mm
• CPU: AVR64DB48
• H-Bridge: BD63573NUV
• Voltage: OPA521

Kicad

Schematic | Layout | Gerber

Firmware

Filename structure: { pcb }{ code }{ version }.hex

Example: C12F0001.hex

	Description
pcb	Name of matching hardware (C12)
code	Type of code contained (R=rom, B=bootloader, F=flash, U=bld update, P=UPDI factory code)
version	Release version (####)

Firmware files

UPDI / Fuses

The fuse settings as well as the P-code (C12Pxxxx.hex) has to be installed by using UPDI.

Fuses Setting
<img src=supplemental/images/C12_fuses.jpg width=500>

Images

YouTube

See the C12 booster in action.

This project is intended for hobby use only and is distributed in accordance with the Apache License 2.0 agreement.