USB FOR MCF51

[SecondTechCo]

I am starting a project and want to put in USB.  I need a small foot print.  I have no idea where to start because there is too much information,  I am looking to have my USB appear as a regular COM port on the PC.  I beleive this is called virtual com port.  Its an MCF51JM project.   I have a few questions ?  Are there virtual com port code examples for code warrior 10 out there ?   What is the difference between CMX stack and freescale stack.  Should I start with one of those  ?  Whats the best reference material ?

[BlackNight · Accepted solution]

Using USB-to-Serial is called CDC (Communication Device Class).

I suggest you start with the DEMOJM (Flexis JM Demonstration Board Product Summary Page) board for which many examples are available.

I used the CMX stack (for USB host class), but I do not recommend using it: it has not been updated for a long time.

I recommend that you start with the Freescale USB stack (current version is V4.0.3): USB Stack Product Summary Page

It comes with many examples for many boards, and has Processor Expert component included.

If you are interested in another version with Eclipse+Processor Expert, then here are CDC related posts: USB on MCU on Eclipse, and additional example projects are here: PE_CDC_V1JM128

[SecondTechCo]

I have the demojm board.  I found the CDC class demo from the Freescale USB Stack 4.0.3.   The Demo compiled and runs fine but when it trys to install on Windows (7), Windows doesnt find the CDC driver for it .  I beleive the problem may be that there is not INF file to tell windows to use the generic CDC driver for this device.   Has anyone tried the CDC peripheral demo and run into the same thing ?   If so, is there an inf file for the project.

[BlackNight]

I had to create my own (merged) .inf file for this, and create it with Processor Expert out of the USB Stack 4.0.2 (or 4.0.3). Project is described on  USB or not: CDC with Processor Expert

and most actual component sources are on GitHub, and projects are here: PE_CDC_V1JM128.

I have attached the .inf file I'm using.

[JimDon]

CDC_MCF51JM128_MCU10.3.zip seems to have gone missing?

"The requested URL /EmbeddedComponents/Examples/Example_PE_CDC_V1JM128/CDC_MCF51JM128_MCU10.3.zip was not found on this server."

[BlackNight]

Hi Jim,

thanks, I have fixed the broken links.

[SecondTechCo]

If you are looking for a sample project the current one in the Freescale USB stack seems to work great for a virtual com port.

[JimDon]

Well for one thing I was telling Erich his link seems broken.

Have you stress tested the current FSL USB stack CDC device? If you send in as tight a loop as you can what kind of throughput do you see? It's possible (but not easy) to get 400K to 600K bytes per second from a CDC device, but you need to have the code to do the right things. Although you can only have a 64 byte packet, you can can tell the poll have more than  that and the driver will do more reads during that poll.

Or have you just exchanged  characters with a terminal program?

[SecondTechCo]

Thanks !  I eventually found this link too.USB CDC INF FIle for Vista 64

[SecondTechCo]

In the manual for the new stack (USBUG revision 12).  It says:

Virtual Communication

(COM) Demo

This chapter provides the setup and running Communication Device Class (CDC) demo

using USB stack – Kinetis k40, S08, CFV1, and CFV2 devices are used as examples.

In this manual, there is no such chapter and nothing about a virtual com.    So is there more information anywhere on where to find this virtual com demo and the information on setup the manual describes ?

[SecondTechCo]

I found what I am looking for in the USBHOSTUG.PDF.

[SecondTechCo]

The application is simple - need the sample to be a com port in Windows