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Re: Porting trouble


On Fri, May 24, 2002 at 10:55:21AM +0200, Christer Kaivo-oja wrote:
> Hi.
> 
> I am currently trying to make a platform port of eCos onto a strongarm 1110 
> board (Keith & Koep's Trizeps board). Now, I'm having trouble getting 
> started...
> 
> What I am trying to do it to get _any_ indication that code is actually 
> running or if it's in some form of exception state... I am basing my port on 
> the assabet platform.
> 
> What I've done so far is to try to find the _first_ piece of code that's run 
> at startup and put a small "flash-the-diodes" endless loop before anything 
> happens, but there is no response... As far as I've seen, it's the 
> reset_vector function in packages/hal/arm/arch/current/src/vectors.S that 
> should be the entry point. Am I right in this?
> 
> I am able to compile a stand-alone diode flashing program and download it to 
> the target. I'm not too familiar with the linker scripts either, so I'm sort 
> of stuck... Anyone have ideas?

The ARM HAL should already be playing with the LEDs, assuming the
specific target supports LEDs. See the comment in vectors.S

// CYGHWR_LED_MACRO can be defined in hal_platform_setup.h. It's free to
// use r0+r1. Argument is in "\x" - cannot use macro arguments since the
// macro may contain #-chars and use of arguments cause these to be 
// interpreted as CPP stringify operators.
// See example in PID hal_platform_setup.h.

But later on its says...

// We cannot access any LED registers until after PLATFORM_SETUP1

I guess this is because before PLATFORM_SETUP1 nothing is setup, The
GPIO pins connected to the LEDs could inputs not outputs etc....

You probably want to look at the PLATFORM_SETUP1 macro and see where
its safe to start using LEDs and work from there. 

    Andrew




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