rock5b_can_pwr/Readme.md

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# ROCK 5B High-Power CAN-Bus & Power HAT ("The Beast")
> 🌍 **Languages:** [English](Readme.md) | [Deutsch](Readme.de.md)
![3D view](img/hat.png)
## Table of Contents
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- [ROCK 5B High-Power CAN-Bus & Power HAT ("The Beast")](#rock-5b-high-power-can-bus--power-hat-the-beast)
- [Table of Contents](#table-of-contents)
- [About the Project](#about-the-project)
- [Features & Technical Specifications](#features--technical-specifications)
- [⚡ Power Distribution (Split-Path Architecture)](#-power-distribution-split-path-architecture)
- [**🚀 Native CAN-Bus**](#-native-can-bus)
- [🔌 Poka-Yoke Connectors](#-poka-yoke-connectors)
- [Pinout](#pinout)
- [J102 - TOOLHEAD (4-Pin Micro-Fit Square)](#j102---toolhead-4-pin-micro-fit-square)
- [J103 - SPIDER / MCU (3-Pin Micro-Fit Row)](#j103---spider--mcu-3-pin-micro-fit-row)
- [J_LCD - MONITOR (4-Pin Micro-Fit Row)](#j_lcd---monitor-4-pin-micro-fit-row)
- [Status LEDs ("Mouse Cinema")](#status-leds-mouse-cinema)
- [Software Configuration (Radxa OS / Armbian)](#software-configuration-radxa-os--armbian)
- [1. Enable Overlay](#1-enable-overlay)
- [2. Configure Interface](#2-configure-interface)
- [3. Klipper Configuration](#3-klipper-configuration)
- [Manufacturing Notes (BOM & PCB)](#manufacturing-notes-bom--pcb)
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## 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.