ROCK 5B High-Power CAN-Bus & Power HAT ("The Beast")

🌍 Languages: English | Deutsch

Table of Contents

• ROCK 5B High-Power CAN-Bus & Power HAT ("The Beast")
  • Table of Contents
  • About the Project
  • Features & Technical Specifications
    • ⚡ Power Distribution (Split-Path Architecture)
    • 🚀 Native CAN-Bus
    • 🔌 Poka-Yoke Connectors
  • Pinout
    • J102 - TOOLHEAD (4-Pin Micro-Fit Square)
    • J103 - SPIDER / MCU (3-Pin Micro-Fit Row)
    • J_LCD - MONITOR (4-Pin Micro-Fit Row)
  • Status LEDs ("Mouse Cinema")
  • Software Configuration (Radxa OS / Armbian)
    • 1. Enable Overlay
    • 2. Configure Interface
    • 3. Klipper Configuration
  • Manufacturing Notes (BOM & PCB)
  • License

About the Project

This HAT was developed to turn the Radxa Rock 5B into the ultimate control center for high-performance laser plotters and 3D printers (Klipper). It addresses the specific weaknesses of standard solutions:

1. Stable Power Supply: Delivers massive 5.2V/6A for the SBC and peripheral USB-C touchscreens.
2. Native CAN Performance: Uses the integrated CAN controller of the RK3588 instead of slow SPI bridges.
3. Thermal Management: A special "donut" design allows the CPU fan to draw fresh air through the PCB.

Features & Technical Specifications

⚡ Power Distribution (Split-Path Architecture)

The board separates power paths for maximum safety and performance:

• Input: 24V DC via reverse-polarity protected XT30 (High Current) connector.
• High-Power Path (Laser/Toolhead):
  • Massive 3-layer copper connection.
  • Direct 24V passthrough to toolhead (up to 120W+ possible, depending on power supply).
  • Protected by SMBJ24A TVS diode against inductive voltage spikes (Back-EMF).
• Logic Path (SBC & Display):
  • Protected by 2A Fast fuse (Littelfuse 0466 series, 63V rating).
  • DC/DC Converter: TI TPS56637 Synchronous Buck Converter.
  • Output: 5.2V (compensates for voltage drop on cables) at up to 6A.

🚀 Native CAN-Bus

• No USB adapters or SPI chips (MCP2515) required.
• Uses the native CAN1 Controller of the RK3588 (Pins 32/33).
• Transceiver: TI SN65HVD230 (3.3V Logic).
• ESD Protection: NUP2105L diode on data lines.
• Termination: 120Ω termination resistor switchable via solder jumper (JP1).

🔌 Poka-Yoke Connectors

Uses Molex Micro-Fit 3.0 with different pin counts to physically prevent fatal miswiring (e.g., 24V to 5V input).

Port	Type	Pins	Description
24V IN	XT30	2	Main input from power supply.
TOOLHEAD	Micro-Fit	2x2 (4-Pin)	24V High-Current + CAN data to laser/print head.
CONTROLLER	Micro-Fit	1x3 (3-Pin)	Pure data connection to MCU mainboard (e.g., Spider).
MONITOR	Micro-Fit	1x4 (4-Pin)	2x 5.2V / 2x GND for powering external displays.

Pinout

J102 - TOOLHEAD (4-Pin Micro-Fit Square)

This is where the laser or print head is connected.

1. 24V (Unfused, High Power)
2. GND
3. CAN_L
4. CAN_H

J103 - SPIDER / MCU (3-Pin Micro-Fit Row)

Connection to mainboard. Galvanically isolated from 24V.

1. GND
2. CAN_L
3. CAN_H

J_LCD - MONITOR (4-Pin Micro-Fit Row)

Power supply for USB-C monitors or HDMI displays.

1. +5.2V
2. +5.2V
3. GND
4. GND

Status LEDs ("Mouse Cinema")

The board features two labeled LEDs for quick diagnosis:

• 24V input present (fuse intact).
• 5.2V logic voltage stable (Power Good signal from TPS56637).

Software Configuration (Radxa OS / Armbian)

Since the native CAN controller is used, setup is extremely simple.

1. Enable Overlay

Add the overlay for the CAN1 controller.
Via rsetup:
Hardware -> Overlays -> Enable CAN1-M1 on GPIO3 (Pins 32/33).
Manually (/boot/extlinux/extlinux.conf):
Add rk3588-can1-m1 to the fdtoverlays line.

2. Configure Interface

Create /etc/network/interfaces.d/can0 for autostart:

allow-hotplug can0 
iface can0 can static  
    bitrate 500000  
    up ip link set $IFACE txqueuelen 1024

3. Klipper Configuration

In printer.cfg:

[mcu]  
canbus_uuid: <your_uuid>  
# No more "serial:" entries!

Manufacturing Notes (BOM & PCB)

• PCB Specs: 4-Layer (Signal / GND / Power / Signal), 1oz copper.
• GPIO Header: A Stacking Header (Extra Tall, min. 11mm spacer height) is absolutely required to provide clearance from the CPU cooler.
• Soldering: Due to massive ground and power planes, a preheater plate (printer heated bed) or preheating in an oven (100°C) is strongly recommended.

Critical Components (LCSC):

• Buck Converter: TPS56637RPAR
• Inductor: MDA1350-2R2M (2.2µH, Isat > 15A, Shielded)
• Transceiver: SN65HVD230
• Fuse: Littelfuse 0466002.NRHF (2A, 63V Rating!)

Disclaimer:
This design works with high currents and voltages. Use at your own risk. Make sure cable cross-sections are rated for the load of your laser/hotend.

License

This project is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (CC BY-NC-SA 4.0).

This means you are free to:

• Share — copy and redistribute the material in any medium or format
• Adapt — remix, transform, and build upon the material

Under the following terms:

• Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made
• NonCommercial — You may not use the material for commercial purposes
• ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license

For the full license text, visit: https://creativecommons.org/licenses/by-nc-sa/4.0/

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Note: The original documentation is in German (Readme.de.md). This English version is a translation for international users.