newbie - Writing drivers for FreeRTOS

cinese wrote on Thursday, September 20, 2007:

Hi guys, I am a newbie here.

Is there any tutorial on how to create device drivers for FreeRTOS? If not, could somebody give me some guidelines and hints?


bkastel1 wrote on Thursday, September 20, 2007:


the basics are very simple. If you want to write drivers for let’s say LCD, then you must decide if all task are allowed to send data directly to LCD or not:
  -If yes then you would use semaphore to get access to the LCD and write data, then you
   would release that semaphore.
  -if not then you write an LcdTASK and you can send data to it using queues.
Besides this the rest of the code isn’t that much different from a driver which is not used in an RTOS based code. Read some code samples that are included in the demo applications and you will get the picture. this demo code is very well written and very well commented.



cinese wrote on Thursday, September 20, 2007:

Ok, I must say I haven’t written any driver at all so far and I am getting confused. I was reading about how to write Linux drivers, but I am starting thinking things are quite different with RTOS. I mean, I don’t need to bother about major/minor numbers, registering modules to the kernel and stuffs like that with RTOS, do I?

I am currently working on the PC Demo and I would like to add some driver, or at least to prepare a tutorial to show how to perform this task. Let’s say I want to write a driver for my USB port:

1. Is it correct to say I actually need more than one driver: one to communicate over USB and then one for each kind of device I want to plug into my USB port?

2. Which are the basic steps I need to follow in order to write such drivers? Is it correct to say it basically comes to sending proper messages to the correct addresses?

Thank you,