AVR-Chat

Hi All,
I like to use bootloaders and have that working quite succesfully.

I like the idea of using certain routines in the boot code from my 
application code to conserve space in the application program , by 
utilizing potentially unused code in the boot page.  Ie. async I/O, 
string routines, and other routines used int the bootloading are 
usefull in other code.  In addition other utilities could be tucked 
away in there, which have nothing to do with bootloading but fill up 
unused space in the bootblock.  Ie LCD drivers could reside there, 
OUTHEX, INHEX, OUTBYTE,INBYTE etc. etc.

I placed a jump table at the start of the bootloader (with the first 
jump to the bootloader of course) followed by jumps to my utilities 
that I wish to call).
Result, whenever I attempt to call any routine from the application 
by using CALL or ICALL, it goes into the bootloading routine Ie. 
effectivily RESETS.  IE. CALL 0xf801 ; getchar 

Perusing the data sheets for the ATMEga128, I can't see why this 
should not work, can any guru shed light on where I am going wrong.
 

Regards,
Lee

Guru 
a. A teacher and guide in spiritual and philosophical matters.
b. A trusted counselor and adviser; a mentor.
c. A recognized leader in a field.
d. An acknowledged and influential advocate.

--- In AVR-Chat@yahoogroups.com, "ldevriesau" <lde99881@...> wrote:
> CALL 0xf801 ; getchar 
Did you use jmp (4 bytes) or rjmp (2 bytes) in your jump table?  If 
the former, the destination address is definitely wrong.  If the 
latter, it might be wrong.  Remember that absolute jump and call 
instaructions need *word* addresses.

Don Kinzer
ZBasic Microcontrollers
http://www.zbasic.net

Would your chip require RAMPZ to be set to access that space?

Also, check the fuse settings, you can forbid running that code from
the application space.