Re: [ECOS] package definition with CDL

[Robin Kirkham <Robin dot Kirkham at cmst dot csiro dot au>]

On Tuesday, 4 July 2000, joerg.rapka@duagon.com wrote:

> I'm about to port eCos to M68k. My target uses the M68331 microcontroller.
> 
> I have defined a package "M68k" as architecture HAL and I have defined
> a package "my_target" as platform HAL.
> 
> I try to find out what are the HAL packages between.
> 
> The M68331 microcontroller is one of the M683xx family. So the M683xx is a
> variant
> of the M68k architecture. My first idea was to define the package "M683xx"
> ...
>
> Or any other idea how to define the packages for the M68k?

Beware, the 68k family is complicated. Many people assume, for instance, 
that all the 683xx have the same CPU, but different IO peripherals.
This is not true.

Motorola use at least three different CPU cores in the 683xx series
microcontrollers:

    EC68000
    CPU32
    CPU32+

These are in addition to the cores of their standard microprocessor line,
68000, 68010, 68020, 68030, 68040, 68060. The EC68000 is maybe the
same as the 68000, but the CPU32 and CPU32+ are both unique.

[There is also the Coldfire line to consider. gcc regards this as part of
the 68k family.]

This suggests to me a four-level HAL structure:

    + architecture 68k HAL
    + architecture variant HAL
	(for each of the 68000, 68010, 68020, ..., EC68000, CPU32,
	    and CPU32+ cores)
    + chip variant HAL
	(for each of the 68000, 68010, 68020, ..., 68300, 68331, 68332,
	    68333, ..., chips)
    + platform HAL
    
I don't know enough about eCos and in particular its HALs to comment further.

I would, however, hope that an eCos HAL structure could be developed that
fits the whole 68k family (even if not all tartgets are initially supported)
without lots of "the same but different" code.


Robin Kirkham			CSIRO Manufacturing Science and Technology
Project Engineer		Locked Bag 9, Preston 3072, Australia
robin.kirkham@cmst.csiro.au	Phone: +61 3 9662-7756  Fax: +61 3 9662-7853