Go Down

Topic: Raspberry Pi launch farce (Read 21 times) previous topic - next topic

Grumpy_Mike

The latest disappointment is that the Pi can't do real interrupts.

Quote
The poll() system call waits for an event on a file descriptor. Your program stops running and the kernel takes over, allowing other "stuff" to run until the kernel itself sees the event, then it un-stalls your program and lets it run.


in this thread:-
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=33&t=10377

As I said, I don't call that real interrupts but apparently Linux people do.  :~

Coding Badly

As I said, I don't call that real interrupts but apparently Linux people do.  :~


The Linux people need to buy a dictionary.

Nick Gammon

The underlying processor must support interrupts, surely. Even if the kernel doesn't make them available to you.

The more I read about this the more I think the Arduino is the better teaching tool, if you just want to learn microprocessors, interrupts, timers, etc.

Jack Christensen

C'mon, guys. Surely a basic principle of any OS worth its salt is insulating the hardware from the user and vice-versa. This means we don't get to do our own I/O, fiddle with interrupts, etc., instead we have to ask the OS to do it for us. MCUs are cool because we don't have an OS and can have our way with the hardware. Apples and oranges (or, as we used to say, Apples and IBMs). Completely different mindset between the two platforms. Now, most OS allow the user to write tasks that run as part of the OS one way or another. Of course this requires some knowledge of the OS' conventions for good behaviour, lack of which results in a system crash.
MCP79411/12 RTC ... "One Million Ohms" ATtiny kit ... available at http://www.tindie.com/stores/JChristensen/

Graynomad

I get what a couple of the blokes are saying on that thread, ie you can achieve a similar affect by running a separate task etc. But the bottom line is this

Quote
Your program stops running and the kernel takes over,


That ain't no interrupt, at least not as it's been known ever since God was a boy, maybe they should be using different terminology.

It certainly looks to me that good as it may be in many areas the RPi is not suitable for bare-metal people.

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

Go Up