RTB_C02

My C02 module is designed to trace DCC Railcom traffic for decoder debugging and development purposes. In particular the Railcom capture is an important feature and helps to validate if a decoders is RCN-217 compliant. The C02 uses the Vt100 terminal emulation control codes for its user interface. Therefore a VT100 capeable terminal program is a must (e.g. putty, teraterm). The USB interface is galvanically isolated from the DCC track potential.

User Guides

• User Guide - DE
  
• User Guide - EN

<img src=supplemental/images/C02_main.jpg width=860>

Hardware

My current PCB layout uses SMD footprints with 0.5mm pitch and mostly 0603 but some 0402 parts. Reflow soldering is my recommendation, but with some experience handsoldering may also be possible.

PCB

• 4-layer PCB, FR4, 1.6mm
• CPU: mega328pb
• USB: FT232x (Mini-B)
• DC/DC: NME0505SC (or compatible)

Kicad

Schematic | Layout | Gerber

Dependency

:yellow_circle: Requires my Kicad project library RTB_SamacSys in the same directory tree.

Firmware

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

Example: C02F0001.hex

	Description
pcb	Name of matching hardware (C02)
code	Type of code contained (R=rom, B=bootloader, F=flash, U=bld update, P=UPDI/SPI factory code)
version	Release version (####)

ISP

The fuse settings as well as the P-code (C02Pxxxx.hex) has to be installed by using the ISP.

Details

CAUTION: Before connecting the ISP, the jumper next to the ISP 6-pin interface must be closed (yellow jumper on picture).

Fuses Setting	Bootloader Install
<img src=supplemental/images/C02_updi_fuses.jpg width=500>	<img src=supplemental/images/C02_updi_memory.jpg width=500>

Bootloader

Subsequent main code updates can be done via uploading the new firmware (C02Fxxxx.hex) file to the bootloader console prompt.

Details

• press F1 to switch to console screen

• press ^b (ctrl-b) to enter bootloader

• upload the firmware file (C02Fxxxx.hex)

• press x to exit the bootloader

  <img src=supplemental/images/C02_debugIF.jpg>

Software

Operating the C02 is within the terminal window.

Terminal screens

Below some example screens of the different functional sections. The screens (called aspects) can be switched by pressing F1-F7. All screens are updated in real-time speed, ensuring always up-to-date information shown.

Aspect	Example
F1: Console prompt.	<img src=supplemental/images/C02_screen_F1.jpg width=500>
F2: DCC/Railcom line by line real-time trace.	<img src=supplemental/images/C02_screen_F2.jpg width=500>
F3: DCC/Railcom decoder payload	<img src=supplemental/images/C02_screen_F3.jpg width=500>
F4: DCC/Railcom timing	<img src=supplemental/images/C02_screen_F4.jpg width=500>
F5: DCC command set	<img src=supplemental/images/C02_screen_F5.jpg width=500>
F6: Railcom response set	<img src=supplemental/images/C02_screen_F6.jpg width=500>

Images

This is how the PCB looks like.

<img src=supplemental/images/C02_samples.jpg width=260> <img src=supplemental/images/C02_closeup.jpg width=260> <img src=supplemental/images/C02_usecase.jpg width=260>

YouTube

Some short videos to see the DCC/Railcom logger in action.