Paging on a MC9S12

[sgriffi3]

Hello Everyone,

I am a computer engineering student at Gonzaga University, and am  
working on a delivery robot with 3 other guys for our senior design  
project. We are using a MC9S12DP512 processor on an Axide CMD-12DP512  
board. We are using AxIDE for our coding and debugging which uses the  
GNU compiler. On this processor we are running a simple multi-tasking  
executive that we wrote in C to control program flow.

We have reached a very bad point. Our code has grown to take up more  
room than we have in the internal flash (from 0xC000 to 0xFFFF). I  
know that the MC9S12 is capable of paging, but I am at a loss as to go  
about using paging. I was wondering if someone could point me in the  
right direction for some documentation or some simple example code or  
application notes.

I also realize that I can just code everything in Assembly to help  
with the size of the code, however a lot of the information is HMI  
pages, which are about the same size in C as in Assembly.

Any help would be much appreciated. If I need to provide more  
information, just lat me know.

Thank you,
Scott

[Edward Karpicz]

Scott wrote:

> We have reached a very bad point. Our code has grown to take up more
> room than we have in the internal flash (from 0xC000 to 0xFFFF). I

You code can keep growing without using paging, while it fits between
nonpaged 0x4000 and 0xFFFF.

Edward


----- Original Message -----
From: <sgriffi3@...>
To: <68HC12@...>
Sent: Monday, March 16, 2009 12:12 AM
Subject: [68HC12] Paging on a MC9S12

> Hello Everyone,
>
> I am a computer engineering student at Gonzaga University, and am
> working on a delivery robot with 3 other guys for our senior design
> project. We are using a MC9S12DP512 processor on an Axide CMD-12DP512
> board. We are using AxIDE for our coding and debugging which uses the
> GNU compiler. On this processor we are running a simple multi-tasking
> executive that we wrote in C to control program flow.
>
> We have reached a very bad point. Our code has grown to take up more
> room than we have in the internal flash (from 0xC000 to 0xFFFF). I
> know that the MC9S12 is capable of paging, but I am at a loss as to go
> about using paging. I was wondering if someone could point me in the
> right direction for some documentation or some simple example code or
> application notes.
>
> I also realize that I can just code everything in Assembly to help
> with the size of the code, however a lot of the information is HMI
> pages, which are about the same size in C as in Assembly.
>
> Any help would be much appreciated. If I need to provide more
> information, just lat me know.
>
> Thank you,
> Scott
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>

[Nigel Johnson-2]

One relatively painless way to use expanded memory is to move functions
up there, and call them with the call directive, returning with an RTC
instead of an RTS.

I am not sure how you would do this in C, never been there.

good luck,

Nigel Johnson
ve3id/g4ajq