An embedded CAN bus interface to send and receive Data with a baudrate of 125 kbt/s in C and assembly, developed on Raspberry Pi Pico based on the programmable I/O module and Pico state machines.
The Controller Area Network a.o. CAN was originally developed for the automotive industry. It's the most common application, therefore it's used in electronic networking in vehicles. However, over the last 20 years, other industries have noticed the advantages and reliability of the CAN bus and have adopted it for a variety of applications. For example, railway applications such as trams, metros, light rail and long-distance trains are equipped with CAN. The CAN bus can be found on numerous levels and in a wide variety of networks in these vehicles, for example to connect door units, in brake controls or in passenger counters. The CAN is also used in aircraft with aircraft with flight status sensors and navigation systems in the cockpit. In addition, CAN buses are found in numerous aerospace applications, from in-flight data analysis to control systems for aircraft engines such as fuel systems, pumps and linear drives.
Programmable I/O (PIO) is a hardware component developed for the Raspberry Pi Pico. It enables the creation of new or additional types of hardware interfaces on the Raspberry Pico-based device. Given the intended peripherals on an MCU and the need for four UART or SPI or other communication buses that the RP2040 does not supported by the RP2040, programmable I/O can solve this problem.
Assuming that the Software is Already built and executed on the Raspberry Pi pico and all the Dependecies are installed and settled ,the user can send and receive data via the CAN Bus with a baudrate of 125 kbt/s.
To sent data the user should choose first in the code the Message identifier and the data to be sent.the default setteled Message Id is 0x446 and 8 Bytes Data will be sent from 0x00 to 0x07, then the user should press the button to send data via the CAN bus.
When data are received ,they will be Automatically pushed from the Input shift register into the FIFO and then will be processed on the USB console, the received Message ID and Data bytes will be also displayed on the console then they will be stored in an Array of structure containing CAN Bus Data.
The Raspberry Pi Pico C-SDK should be installed with the ARM C compiler , these can be done by following these Link Getting Started With Raspberry Pi Pico .
The MCP2555 should be wired with the CAN_high and CAN_Low to handle transformation of binary message to Analogue message due to voltage differentiation. The complete Layout should be like below:
the Sent and Read of the Data will run parallel in the same Time. Sending data have his own thread called on the pico Core . and reading of data has his own Core
The Raspberry Pi Pico C-SDK should be installed from source. and this project should be cloned on the local host then :
To run this project on the Raspberry Pi pico , the CAN_Rx.uf2 should be copied from the build folder into the Raspberry Pi pico.
Changes like New Message_ID or the Data Byte that should be sent can be done from CAN_Rx.c . than the user shoud build the project . to do
that run :
cmake ..
than :
make