programming concepts for CAN and USB protocols

[Jinzpaul4u]

Hi there,

Good wishes!

I've to understand the programming concepts for CAN and USB protocols, with interfacing details too. I'm using ARM Cortex M-4 ic's (STM32F405xx). Does anyone can help me for this attempt.
Please suggest to me some good tutorials and websites for learning both protocols.


Thanks in Advance!

 

[bigdogguru]

Actually some of the best general CAN resources are available on the Microchip website:

AN713 - Controller Area Network (CAN) Basics

AN228 - A CAN Physical Layer Discussion

Webinar - Introduction to Controller Area Network (CAN)


Other general CAN bus reference:

Official CAN in Automationsite

CANbus


STM32 specific information:

KEIL STM32 CAN Example

AN3154 - CAN protocol used in the STM32™ bootloader



By the way this site is a good resource for STM32 related documenation:

STM32 CORTEX M0, M3 and M4


BigDog

 

[Jinzpaul4u]

Thanks for the feedback..

How about USB programming ?

any solutions available to learn ?

 

[bigdogguru]

It depends which class of USB device you wish to implement.

Typically the simplest and most straight forward class implement is the Communication Device Class (CDC), which can emulate a serial port by establishing a Virtual COM Port (VCP).


There are several advantages to a CDC implementation with Serial Emulation:

The first being there are no custom drivers required for the PC as it typically utilizes drivers already available in a windows installation, only modification of the INF to include the appropriate VID/PID is required.

The second being as the VCP emulates a standard serial port, legacy software can channel I/O through the designated COMx, just as if it were a normal RS-232 port.

The third being, the API is rather simple and quite similar to that of controlling a standard UART/RS-232 implementation.


STM32 USB Full Speed Device Library

STM32 Firmware Libraries and USB Development Kit



Reference Section 6 Virtual COM port demo:

STM32 USB-FS-Device Development Kit User Manual


BigDog

 

[Jinzpaul4u]

Hi,

I'm very pleased with the help you did. I got a Sample code from Microchip site for CAN protocol :

https://ww1.microchip.com/downloads/en/DeviceDoc/CE128_ECAN_FIFO_061008.zip

when I went through code, got one more doubt too.That is,why they're using DMA for CAN communication? is it mandatory to use ? excuse me, I do not have any programming experience on DMA .

 

[bigdogguru]

That is,why they're using DMA for CAN communication? is it mandatory to use ? excuse me, I do not have any programming experience on DMA .

No it is not required.

In fact many microcontrollers do not offer any DMA channels.

I would recommend starting your studies of CAN bus by watching the webinar video presentation I posted in reply #2.

BigDog

 

[Jinzpaul4u]

it might be helpful

advanced pic microcontroller projects in c from usb to rtos with the pic18f series by dogan ibrahim

 

[Jinzpaul4u]

Hi there,

I've been working on ECAN Interface with dspic33fj and its going nicely.

I've a doubt about OSI reference model.

1. What does mean by a frame in embedded communication?
2. How do we differentiate
* a frame of data?
* a byte of data?
* a packet of data?
3. What is the standard length reqiured for a frame?
4. CAN protocol using 2 lower level of OSI reference model for byte of data transmission/reception . but we're sending data as a frame, fame belongs to network section in OSI model. Is it CAN protocol using network layer too?

Any kind of feedback would be greatly appreciated !

Thanks in advance.