AVR-Chat

I'm attempting to convert the AVR Butterfly demo program to WinAVR from Atmel's
CodeVision version.  The program currently contains something like:

__flash char foo_1[] =   { 0, 1 };
__flash char foo_2[] =   { 2, 3 };

__flash char __flash *foobar[] = { foo_1, foo_2 };


I'm trying to create the gcc equivalent.  Studying avr-libc documentation: a
start is:

#include <avr/pgmspace.h>

prog_char foo_1[] =   { 0, 1 };
prog_char foo_2[] =   { 2, 3 };

<the puzzle> foobar[] = { foo_1, foo_2 };

But I haven't figured out <the puzzle>


While I'm at it:  Is there a good web resource for (finally) learning about the
details of more complex array and pointer declarations (arrays of pointers to
functions, arrays of pointers to arrays of yada, yada ....).  I have never
gotten this stuff "clear" in my head so that I can deal with these things
without researching it. ... the bulb has just never come on full brightness on
this subject :-) 

Thanks in advance for your help ...

Cheers,

Chuck Hackett
"Good judgment comes from experience, experience comes from bad judgment"
7.5" gauge Union Pacific Northern (4-8-4) 844
http://www.whitetrout.net/Chuck

Chuck Hackett wrote:

> I'm attempting to convert the AVR Butterfly demo program to WinAVR 
> from Atmel's
> CodeVision version.  The program currently contains something like:
>
> __flash char foo_1[] =   { 0, 1 };
> __flash char foo_2[] =   { 2, 3 };
>
> __flash char __flash *foobar[] = { foo_1, foo_2 };
>
>
> I'm trying to create the gcc equivalent.  Studying avr-libc 
> documentation: a
> start is:
>
> #include <avr/pgmspace.h>
>
> prog_char foo_1[] =   { 0, 1 };
> prog_char foo_2[] =   { 2, 3 };
>
> <the puzzle> foobar[] = { foo_1, foo_2 };
>
I cut and pasted some working code and changed the names. It should work 
for you.

#include <avr/pgmspace.h>

static const prog_uint8_t foo_1[] = {0, 1 };
static const prog_uint8_t foo_2[] = {2, 3 };                          
                 
const prog_uint8_t *foobar[] PROGMEM = { foo_1, foo_2 };

PGM_P pArrayPointer;
uint16_t index;

index = 1;
pArrayPointer = (PGM_P)&(foobar[index]);
this_byte = pgm_read_byte(pArrayPointer)/2; 

Mike
http://home.austin.rr.com/perks/micros/

> From: Mike Perks
> 
> Chuck Hackett wrote:
> 
> > I'm attempting to convert the AVR Butterfly demo program to WinAVR
> > from Atmel's
> > CodeVision version.  The program currently contains something like:
> >
> > __flash char foo_1[] =   { 0, 1 };
> > __flash char foo_2[] =   { 2, 3 };
> >
> > __flash char __flash *foobar[] = { foo_1, foo_2 };
> > ....
>
> I cut and pasted some working code and changed the names. It should work
> for you.
> 
> #include <avr/pgmspace.h>
> 
> static const prog_uint8_t foo_1[] = {0, 1 };
> static const prog_uint8_t foo_2[] = {2, 3 };
> 
> const prog_uint8_t *foobar[] PROGMEM = { foo_1, foo_2 };
> ....

Thanks Mike.  This, along with dozens of other changes and at least I have a
clean compile now.

I'm off to try loading the Butterfly now.

Cheers,

Chuck Hackett
"Good judgment comes from experience, experience comes from bad judgment"
7.5" gauge Union Pacific Northern (4-8-4) 844
http://www.whitetrout.net/Chuck