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Re: [avr-libc-dev] AT43USB35x support!

From: Keith Gudger
Subject: Re: [avr-libc-dev] AT43USB35x support!
Date: Fri, 28 Feb 2003 15:36:39 -0800 (PST)

The 320 supports 16 address lines for *words* of external Program Memory.
The PC is 16 bits wide.  There is NO RAMPZ register.  SO, I guess what
this means is that one could have up to 64K of program code, but LPMs
would only be able to get to the bottom 32K?  I don't think any of us here
looked at this in detail - We've never put more than a 16K *byte* FLash on
the thing.  

I don't have any easier questions...


On Sat, 1 Mar 2003, Marek Michalkiewicz wrote:

> On Fri, Feb 28, 2003 at 10:34:49PM +0100, Joerg Wunsch wrote:
> > Are they for IAR compatibility?  If that's the case, we might move them
> > out to <compat/ina90.h> (doesn't exist yet in that directory).  Hmm,
> > just a thought.  Alternatively, we could e. g. define a symbol like
> > __COMPAT_IAR there, and maintain device-specific IAR compatibility
> > defines inside the various ioXXX.h files.  It would be nice to have
> > them universally available, i. e. to know what to write into the
> > other .h files.  Whatever makes migration between the various compilers
> > easier for our users is IMHO a win.
> OK, I've just added at43usb320 support, and removed the IAR defines
> from both io43u32x.h and io43u35x.h for now (can be added later, when
> we decide what is the best place for them, ideally for all devices).
> One thing about the at43usb320 is not clear to me - it appears to
> support 128K bytes (64K*16) of external program memory, but if
> FLASHEND is defined as 0x1ffff, RAMPZ must be defined, otherwise
> gcrt1.S (using ELPM to copy initialized data) fails to build.
>  a. RAMPZ exists, but the datasheet forgot to document it
>  b. RAMPZ doesn't exist, upper 64K is only for executable code
>  c. RAMPZ doesn't exist, upper 64K is a mistake in the datasheet
>  d. give me an easier question ;)
> What is the correct answer?
> Thanks,
> Marek

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