128 lines
4.4 KiB
Markdown
128 lines
4.4 KiB
Markdown
# ROCK 5B High-Power CAN-Bus & Power HAT ("The Beast")
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## About the Project
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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:
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1. **Stable Power Supply:** Delivers massive 5.2V/6A for the SBC and peripheral USB-C touchscreens.
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2. **Native CAN Performance:** Uses the integrated CAN controller of the RK3588 instead of slow SPI bridges.
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3. **Thermal Management:** A special "donut" design allows the CPU fan to draw fresh air through the PCB.
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## Features & Technical Specifications
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### ⚡ Power Distribution (Split-Path Architecture)
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The board separates power paths for maximum safety and performance:
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* **Input:** 24V DC via reverse-polarity protected **XT30 (High Current)** connector.
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* **High-Power Path (Laser/Toolhead):**
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* Massive 3-layer copper connection.
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* Direct 24V passthrough to toolhead (up to 120W+ possible, depending on power supply).
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* Protected by **SMBJ24A TVS diode** against inductive voltage spikes (Back-EMF).
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* **Logic Path (SBC & Display):**
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* Protected by **2A Fast** fuse (Littelfuse 0466 series, 63V rating).
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* **DC/DC Converter:** TI **TPS56637** Synchronous Buck Converter.
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* Output: **5.2V** (compensates for voltage drop on cables) at up to **6A**.
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### **🚀 Native CAN-Bus**
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* No USB adapters or SPI chips (MCP2515) required.
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* Uses the native **CAN1 Controller** of the RK3588 (Pins 32/33).
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* **Transceiver:** TI SN65HVD230 (3.3V Logic).
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* **ESD Protection:** NUP2105L diode on data lines.
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* **Termination:** 120Ω termination resistor switchable via solder jumper (JP1).
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### 🔌 Poka-Yoke Connectors
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Uses **Molex Micro-Fit 3.0** with different pin counts to physically prevent fatal miswiring (e.g., 24V to 5V input).
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| Port | Type | Pins | Description |
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| :---- | :---- | :---- | :---- |
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| **24V IN** | **XT30** | 2 | Main input from power supply. |
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| **TOOLHEAD** | **Micro-Fit** | 2x2 (4-Pin) | 24V High-Current + CAN data to laser/print head. |
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| **CONTROLLER** | **Micro-Fit** | 1x3 (3-Pin) | Pure data connection to MCU mainboard (e.g., Spider). |
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| **MONITOR** | **Micro-Fit** | 1x4 (4-Pin) | 2x 5.2V / 2x GND for powering external displays. |
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## Pinout
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### J102 - TOOLHEAD (4-Pin Micro-Fit Square)
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*This is where the laser or print head is connected.*
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1. **24V** (Unfused, High Power)
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2. **GND**
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3. **CAN_L**
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4. **CAN_H**
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### J103 - SPIDER / MCU (3-Pin Micro-Fit Row)
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*Connection to mainboard. Galvanically isolated from 24V.*
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1. **GND**
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2. **CAN_L**
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3. **CAN_H**
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### J_LCD - MONITOR (4-Pin Micro-Fit Row)
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*Power supply for USB-C monitors or HDMI displays.*
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1. **+5.2V**
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2. **+5.2V**
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3. **GND**
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4. **GND**
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## Status LEDs ("Mouse Cinema")
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The board features two labeled LEDs for quick diagnosis:
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* 24V input present (fuse intact).
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* 5.2V logic voltage stable (Power Good signal from TPS56637).
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## Software Configuration (Radxa OS / Armbian)
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Since the native CAN controller is used, setup is extremely simple.
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### 1. Enable Overlay
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Add the overlay for the CAN1 controller.
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Via rsetup:
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`Hardware -> Overlays -> Enable CAN1-M1 on GPIO3 (Pins 32/33)`.
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Manually (`/boot/extlinux/extlinux.conf`):
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Add `rk3588-can1-m1` to the `fdtoverlays` line.
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### 2. Configure Interface
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Create `/etc/network/interfaces.d/can0` for autostart:
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```
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allow-hotplug can0
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iface can0 can static
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bitrate 500000
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up ip link set $IFACE txqueuelen 1024
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```
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### 3. Klipper Configuration
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In printer.cfg:
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```
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[mcu]
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canbus_uuid: <your_uuid>
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# No more "serial:" entries!
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```
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## Manufacturing Notes (BOM & PCB)
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* **PCB Specs:** 4-Layer (Signal / GND / Power / Signal), 1oz copper.
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* **GPIO Header:** A **Stacking Header (Extra Tall, min. 11mm spacer height)** is absolutely required to provide clearance from the CPU cooler.
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* **Soldering:** Due to massive ground and power planes, a preheater plate (printer heated bed) or preheating in an oven (100°C) is strongly recommended.
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**Critical Components (LCSC):**
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* Buck Converter: **TPS56637RPAR**
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* Inductor: **MDA1350-2R2M** (2.2µH, Isat > 15A, Shielded)
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* Transceiver: **SN65HVD230**
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* Fuse: **Littelfuse 0466002.NRHF** (2A, **63V Rating!**)
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Disclaimer:
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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. |