Lpc2000

Thanks Brendan.

I don't understand the documentation about switching modes.
During startup I cycle thru each mode and allocate a default
stack. After that I switch back to SVC mode. According to the
documentation this should fail as switching from SYS to SVC
can only occur as a result of an exception.

George

On Sat, 2006-02-18 at 06:13 +0000, brendanmurphy37 wrote:

> 
> George,
> 
> I don't know the answer to your specific question off-hand. However, 
> I'm sure you'd find it helpful to get some documentation on ARM 
> processors.
> 
> One of the problems with micros that use standard (as opposed to 
> proprietary) cores, such as ARM, is that the manufacturers tend not 
> to repeat documentation that can be found elsewhere. This is a bit 
> inconvenient.
> 
> The best source for information you require is direct from ARM. 
> Check out the ARM7TDMI Technical Reference Manual, which can be 
> found at: 
> 
> http://www.arm.com/documentation/ARMProcessor_Cores/index.html
> 
> This covers all the LPC2xxx series.
> 
> The standard reference for ARM is the "ARM ARM" (real title: "ARM 
> Technnical Reference Manual"). Unfortuntely, they expect you to pay 
> for this. It's a really useful reference to have though. See:
> 
> http://www.amazon.com/gp/product/0201737191/sr=8-
> 1/qid=1140242347/ref=pd_bbs_1/102-6410308-4751357?%5Fencoding=UTF8
> 
> Hope this helps.
> 
> Brendan
> 
> --- In lpc2000@yahoogroups.com, "George M. Gallant, Jr." 
> <ggallant571@...> wrote:
> >
> > Is it possible to load the SPSR in the lpc2214.
> > 
> > For example:
> > 
> >                    mov    r0, #0xD0           ;set previous mode 
> to user
> >                    msr     spsr_cxsf, r0
> > 
> > I do this at boot and then read and display CPSR & SPSR
> > 
> >         CPSR = 0x000000D3
> >         SPSR = 0x800000D3
> > 
> > George
> > 
> > On Thu, 2006-02-16 at 18:47 +0000, brendanmurphy37 wrote:
> > 
> > > 
> > > The suffix to CPSR refers to which field(s) of the CPSR is 
> > > rereferenced (you can specify one or more). Defined fields are:
> > > 
> > > c - control
> > > f - flags
> > > s - status
> > > x - extension
> > > 
> > > Thus., for example, you can update only those parts of the CPSR 
> that 
> > > are of interest. See a description of the CPSR for details.
> > > 
> > > Brendan
> > > 
> > > --- In lpc2000@yahoogroups.com, "George M. Gallant, Jr." 
> > > <ggallant571@> wrote:
> > > >
> > > > I notice in many assembly language examples the use of CPSR_c
> > > > & CPSR_cxsf but donot understand the differences.
> > > > 
> > > > Thanks,
> > > >     George
> > > > 
> > > > 
> > > > [Non-text portions of this message have been removed]
> > > >
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > SPONSORED LINKS 
> > > 
> > > Microcontrollers 
> > > Microprocessor 
> > > Intel microprocessors 
> > > Pic microcontrollers 
> > > 
> > > 
> > > 
> > > 
> _____________________________________________________________________
> _
> > > YAHOO! GROUPS LINKS
> > > 
> > > 
> > >      1.  Visit your group "lpc2000" on the web.
> > >           
> > >      2.  To unsubscribe from this group, send an email to:
> > >          lpc2000-unsubscribe@yahoogroups.com
> > >           
> > >      3.  Your use of Yahoo! Groups is subject to the Yahoo! 
> Terms of
> > >         Service.
> > > 
> > > 
> > > 
> > > 
> _____________________________________________________________________
> _
> > > 
> > > 
> > 
> > 
> > [Non-text portions of this message have been removed]
> >
> 
> 
> 
> 
> 
> 
> 
> SPONSORED LINKS 
> 
> Microcontrollers 
> Microprocessor 
> Intel microprocessors 
> Pic microcontrollers 
> 
> 
> 
> ______________________________________________________________________
> YAHOO! GROUPS LINKS
> 
> 
>      1.  Visit your group "lpc2000" on the web.
>           
>      2.  To unsubscribe from this group, send an email to:
>          lpc2000-unsubscribe@yahoogroups.com
>           
>      3.  Your use of Yahoo! Groups is subject to the Yahoo! Terms of
>         Service.
> 
> 
> 
> ______________________________________________________________________
> 
> 


[Non-text portions of this message have been removed]