Mirrors_Framework/ODrive
1
0
Fork 0
mirror of https://github.com/odriverobotics/ODrive.git synced 2026-09-24 17:53:39 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

Add Danfoss wiring page link to CAN guide

Browse Source
This commit is contained in:
Paul Guenette
2021-10-24 14:52:05 -04:00
committed by GitHub
parent d4a2ece943
commit 32136b90c3
1 changed files with 5 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files
docs/can-guide.md
+5 -1
View File
@@ -10,8 +10,12 @@ Borrowing from [Wikipeda](https://en.wikipedia.org/wiki/CAN_bus):
In simple terms, CAN is a way of communicating between many devices over a single twisted pair of wires. The signal is transmitted as the difference in voltage between the two wires (differential signalling), which makes it very robust against noise. Instead of using a unique address (like I2C) or a select pin (like SPI), CAN *messages* have a unique ID that also acts as the priority. At the beginning of a message frame, all devices talk and read at the same time. As the message ID is transmitted, the lowest value "wins" and that message will be transmitted (ID **0** has the *highest* priority). All other devices will wait for the next chance to send. If two devices send the same message ID at the same time, they will conflict and a bus failure may occur. Make sure your devices can never send the same message ID at the same time!
See also this great article from Danfoss that quickly describes how to put together the wiring for a CAN bus https://danfosseditron.zendesk.com/hc/en-gb/articles/360042232992-CAN-bus-physical-layer
![CAN picture](screenshots/CAN_Bus_Drawing.png)
## Why use CAN?
CAN is convenient for its simple and robust Physical Layer (PHY) that requires only a twisted pair of wires and a 120ohm termination resistor at each end. It has low jitter and low latency, because there is no host computer. It is relatively fast (CAN 2.0b supports 1 Mbps). Messages are easy to configure and load with data. Transceivers and controllers are inexpensive and widely available, thanks to its use in automotive.
@@ -131,4 +135,4 @@ Instead of manually writing values into the data, we can create a dictionary of
The [CAN DBC Example](../tools/can_dbc_example.py) script shows you how this can be used. This is the recommended method of serializing and deserializing.
If you're using C++, then you can use the [CANHelpers](..firmware/communication/../../../Firmware/communication/can/can_helpers.hpp) single-header library to do this instead, although the DBC file isn't used.
If you're using C++, then you can use the [CANHelpers](..firmware/communication/../../../Firmware/communication/can/can_helpers.hpp) single-header library to do this instead, although the DBC file isn't used.