LPC2000 port - FIQ interrupt

piero74 wrote on Friday, April 18, 2008:

Hi all.

I need to have a very critical interrupt.
So, i decided to use FIQ.
In port.c and port macro.h (for IAR compiler) i changed calls to enable_interrupt and disable_interrupt (with calls to other similar assembler functions, which doesn’t disable FIQ flag in cpsr).

I have some questions:

1. when fiq occurs, it can interrupts both application routines and RTOS critical routines. can be a problem??? (i don’t use rtos api inside fiq routine)
2. for licensing: have i to provide my changes in port with our emebedded device? i’m thinking to add in our website two links, one for freertos download page for official version, and one for a zip file which will have modified files. Is it right?

Bye
Piero
 

rtel wrote on Friday, April 18, 2008:

> 1. when fiq occurs, it can interrupts both application routines and
> RTOS critical routines. can be a problem??? (i don’t use rtos api
> inside fiq routine)

No problem - so long as you don’t use the API from the FIQ (as you say).  This is effectively implementing the configKERNEL_INTERRUPT_PRIORITY feature for the ARM7 -> http://www.freertos.org/a00110.html

>2. for licensing: have i to provide my changes in port with our emebedded
>device? i’m thinking to add in our website two links, one for freertos
>download page for official version,

That’s good.

>and one for a zip file which will
>have modified files. Is it right?

This is quite a common change, which I already have on file should others want to use it, so in this case I don’t think it is necessary to have the .zip file as a download from your site.  The code is already “in the community” - but you definitely do the right thing by asking.

Regards.