nopnop2002
248 lines
8.7 KiB
Markdown
248 lines
8.7 KiB
Markdown
# esp-idf-can2http
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CANbus to http bridge using esp32.
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It's purpose is to be a bridge between a CAN-Bus and a HTTP-Server.
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# Software requirement
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esp-idf v4.2-dev-2243 or later.
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Use twai(Two-Wire Automotive Interface) driver instead of can driver.
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# Hardware requirements
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1. SN65HVD23x CAN-BUS Transceiver
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|SN65HVD23x||ESP32|ESP32-S2|ESP32-C3||
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|:-:|:-:|:-:|:-:|:-:|:-:|
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|D(CTX)|--|GPIO21|GPIO17|GPIO9|(*1)|
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|GND|--|GND|GND|GND||
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|Vcc|--|3.3V|3.3V|3.3V||
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|R(CRX)|--|GPIO22|GPIO18|GPIO10|(*1)|
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|Vref|--|N/C|N/C|N/C||
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|CANL|--||||To CAN Bus|
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|CANH|--||||To CAN Bus|
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|RS|--|GND|GND|GND|(*2)|
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(*1) You can change using menuconfig. But it may not work with other GPIOs.
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(*2) N/C for SN65HVD232
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2. Termination resistance
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I used 150 ohms.
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# Test Circuit
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```
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+-----------+ +-----------+ +-----------+
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| Atmega328 | | Atmega328 | | ESP32 |
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| | | | | |
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| Transmit | | Receive | | 21 22 |
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+-----------+ +-----------+ +-----------+
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| | | | | |
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+-----------+ +-----------+ | |
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| | | | | |
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| MCP2515 | | MCP2515 | | |
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+-----------+ +-----------+ | |
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+-----------+ +-----------+ +-----------+
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| | | | | D R |
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| MCP2551 | | MCP2551 | | VP230 |
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| H L | | H L | | H L |
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+-----------+ +-----------+ +-----------+
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| | | | | |
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+--^^^--+ | | +--^^^--+
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| R1 | | | | R2 |
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|---+-------|-------+-------|-------+-------|---| BackBorn H
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|-----------+---------------+---------------+---| BackBorn L
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+--^^^--+:Terminaror register
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R1:120 ohms
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R2:150 ohms(Not working at 120 ohms)
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```
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__NOTE__
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3V CAN Trasnceviers like VP230 are fully interoperable with 5V CAN trasnceviers like MCP2551.
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Check [here](http://www.ti.com/lit/an/slla337/slla337.pdf).
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# Installation for ESP32
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```
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git clone https://github.com/nopnop2002/esp-idf-can2http
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cd esp-idf-can2http
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idf.py set-target esp32
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idf.py menuconfig
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idf.py flash
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```
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# Installation for ESP32-S2
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```
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git clone https://github.com/nopnop2002/esp-idf-can2http
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cd esp-idf-can2http
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idf.py set-target esp32s2
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idf.py menuconfig
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idf.py flash
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```
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# Installation for ESP32-C3
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```
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git clone https://github.com/nopnop2002/esp-idf-can2http
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cd esp-idf-can2http
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idf.py set-target esp32c3
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idf.py menuconfig
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idf.py flash
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```
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# Configuration
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## CAN Setting
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## WiFi Setting
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You can use static IP.
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You can connect using mDNS.
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## External HTTP Server Setting
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The External HTTP Server receives CAN Bus received data.
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__Note__
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The Built-in HTTP Server receives CAN Bus transmittion data.
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# Definition from CANbus to HTTP
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When CANbus data is received, it is sent by HTTP POST according to csv/can2http.csv.
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The file can2http.csv has three columns.
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In the first column you need to specify the CAN Frame type.
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The CAN frame type is either S(Standard frame) or E(Extended frame).
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In the second column you have to specify the CAN-ID as a __hexdecimal number__.
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In the last column you have to specify the HTTP-POST-Path of external HTTP server.
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Each CAN-ID is allowed to appear only once in the whole file.
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```
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S,101,/post
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E,101,/post
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S,103,/post
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E,103,/post
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```
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When a CAN frame with ID 0x101 is received, POST with the 'canid':257.
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When a CAN frame with ID 0x103 is received, POST with the 'canid':259.
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POST Parameter Example:
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CAN-ID is a decimal number, not a hexadecimal number.
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```
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{"canid":257, "frame": "standard", "data": [16, 17, 18]}
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{"canid":257, "frame": "extended", "data": [16, 17, 18]}
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{"canid":259, "frame": "standard", "data": [16, 17, 18]}
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{"canid":259, "frame": "extended", "data": [16, 17, 18]}
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```
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# Definition from HTTP to CANbus
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Not exist.
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You can send any CAN-ID.
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# Send CANBus frame using curl
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CAN-ID is specified in __decimal number__.
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```
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$ curl -X POST -H "Content-Type: application/json" -d '{"canid": 513, "frame": "standard", "data": [16, 17, 18]}' http://esp32-server.local:8000/api/twai/send
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twai send successfully
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$ curl -X POST -H "Content-Type: application/json" -d '{"canid": 513, "frame": "extended", "data": [16, 17, 18]}' http://esp32-server.local:8000/api/twai/send
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twai send successfully
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```
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CANBus reception using UNO.
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---
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# HTTP Server Using Tornado
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```
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sudo apt install python3-pip python3-setuptools
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python -m pip install -U pip
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python -m pip install -U wheel
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python -m pip install tornado
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cd tornado
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python can.py
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```
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# HTTP Server Using Flask
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```
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sudo apt install python3-pip python3-setuptools
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python -m pip install -U pip
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python -m pip install -U wheel
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python -m pip install -U Werkzeug
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python -m pip install flask
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cd flask
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python can.py
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```
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# Brows received data Using Tornado/Flask
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Open your browser and put the Server's IP in the address bar.
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# Visualize CAN-Frame
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## Using python
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There is a lot of information on the internet about the Python + visualization library.
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- [matplotlib](https://matplotlib.org/)
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- [seaborn](https://seaborn.pydata.org/index.html)
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- [bokeh](https://bokeh.org/)
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- [plotly](https://plotly.com/python/)
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## Using node.js
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There is a lot of information on the internet about the node.js + __real time__ visualization library.
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- [epoch](https://epochjs.github.io/epoch/real-time/)
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- [plotly](https://plotly.com/javascript/streaming/)
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- [chartjs-plugin-streaming](https://nagix.github.io/chartjs-plugin-streaming/1.9.0/)
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# Troubleshooting
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There is a module of SN65HVD230 like this.
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There is a __120 ohms__ terminating resistor on the left side.
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I have removed the terminating resistor.
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And I used a external resistance of __150 ohms__.
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A transmission fail is fixed.
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If the transmission fails, these are the possible causes.
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- There is no receiving app on CanBus.
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- The speed does not match the receiver.
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- There is no terminating resistor on the CanBus.
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- There are three terminating resistors on the CanBus.
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- The resistance value of the terminating resistor is incorrect.
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- Stub length in CAN bus is too long. See [here](https://e2e.ti.com/support/interface-group/interface/f/interface-forum/378932/iso1050-can-bus-stub-length).
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# Reference
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https://github.com/nopnop2002/esp-idf-can2mqtt
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https://github.com/nopnop2002/esp-idf-CANBus-Monitor
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