D22

RTB_D22

My Homebrew D22 decoder is a double sided mobile decoder with Plux16 connector. The decoder is designed to integrate into the RTB digital control infrastructure.

See also

• RTB_D12 - custom (Fleischmann V100)
• RTB_D13 - custom (Minitrix coach)
• RTB_D15 - custom (Minitrix V160)
• RTB_D16 - NEM651
• RTB_D20 - NEM651
• RTB_D21 - Next18
• RTB_D23 - NEM652

User Guides

• User Guide - DE
• User Guide - EN

Decoder features,

• Plux16 connector
• DCC
  • DCC-A automatic logon
  • DCC-R protocol extension
  • Service Mode Programming
• Railcom
  • Channel 1/2
  • POM, xPOM
  • DYN: Speed, QoS, Track-voltage, Motor-current, AUX-current, Temp, Distance travelled
• Double sided
• Dimension: 15 x 11 mm
• 7-20V track voltage
• heartbeat LED
• adjustable max motor current (default 300mA)
• adjustable max AUX current (default 500mA)
• over temp protection
• Function output: LF/LR (dimmable, 1.4kHz) open drain
• Function output: AUX1/AUX2 (dimmable, 1.4kHz) open drain
• Function output: AUX3/AUX4 logic level (3.3V) using LS A/B ports
• Function output: AUX5/AUX6 logic level (3.3V) or ZBCLK/ZBDAT (3.3V)
• optional external buffer capacitor
• <10mA idle power consumption
• Firmware update over main tracks via DCC-R protocol

Hardware

The current PCB layout uses SMD footprints with 0.5mm pitch and 0402 parts. Reflow soldering is mandatory whereas handsoldering near to impossible.

PCB

• 6-layer PCB, FR4, 15 x 11 x 0.8mm (double sided)
• CPU: AVR64DD28
• Motor bridge: DRV8231

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: D22F0001.hex

Firmware files

UPDI

The fuse settings as well as the P-code (D22Pxxxx.hex) has to be installed by using UPDI.
Connecting the decoder via its track pins to a 5V(DC) power supply will boot its CPU. This way, its easy to program the fuses and flash.

<img src=supplemental/images/D22_updi.jpg width=800>

Details

Fuse Setting	P-code Install
<img src=supplemental/images/D22_updi_fuses.jpg width=500>	<img src=supplemental/images/D22_updi_memory.jpg width=500>

Images

YouTube

Some YouTubes to see the D22 decoder in action.

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