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Wipster
Joined: 09 Oct 2008
Posts: 16
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| Putting stuff in ROM |
 Posted: Sat Jan 31, 2009 5:38 pm |
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Hey all,
I'm trying to make a little menu system for my LCD project is there a way I can get this into ROM seeing as none of it will change, so I can save a bit of space?
| Code: |
void Test(void)
{
}
typedef void (*_fptr)(void);
typedef struct MENU_ITEM_STRUCT {
int8 Type;
char Text[10];
_fptr FunctionPntr;
} MENU_ITEM;
MENU_ITEM MainMenu[] = {
{MENU_ITEM_TYPE_MENU_HEADER, "Main menu", Test},
{MENU_ITEM_TYPE_SUB_MENU, "Show", 0},
{MENU_ITEM_TYPE_COMMAND, "About", 0},
{MENU_ITEM_TYPE_END_OF_MENU, "", 0}};
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I kept running into problems with "must evaluate to constant" etc.
I am using a recent compiler.
Edit:- It would be nice if this menu system had sub menus, I was thinking make a link to the parent menu from the submenu, but that would require some forward declarations, and am I right in thinking CCS doesn't like that trickery with structs?
Anyway around it? - I guess I could use a stack of pointers to these tables. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Feb 01, 2009 1:21 pm |
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You need to post your code as part of a test program. See this example:
http://www.ccsinfo.com/forum/viewtopic.php?t=33458
I pasted your code into a framework for 18F452, with #fuses, etc., and
a main(), and I got this error:
| Quote: |
Undefined identifier MENU_ITEM_TYPE_MENU_HEADER |
If you can post a test program that cleans up this kind of error, then
I can work on the function pointer issue in your code, which is what
you really want to get working. |
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Wipster
Joined: 09 Oct 2008
Posts: 16
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| Posted: Mon Feb 02, 2009 1:22 pm |
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Oh woops sorry, ok here it is in a example - I blind programmed this as my board doesn't have an RS232 but it should illustrate what I want to do (and work).
| Code: | #include <18F452.h>
#fuses XT,NOWDT,NOPROTECT,BROWNOUT,PUT,NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
#define MENU_ITEM_TYPE_MENU_HEADER 0
#define MENU_ITEM_TYPE_SUB_MENU 1
#define MENU_ITEM_TYPE_COMMAND 2
#define MENU_ITEM_TYPE_END_OF_MENU 3
void Test(void);
typedef void (*_fptr)(void);
typedef struct MENU_ITEM_STRUCT {
int8 Type;
char Text[10];
_fptr FunctionPntr;
} MENU_ITEM;
MENU_ITEM MainMenu[4] = {
{MENU_ITEM_TYPE_MENU_HEADER, "Main menu", 0},
{MENU_ITEM_TYPE_COMMAND, "Show", Test},
{MENU_ITEM_TYPE_COMMAND, "About", 0},
{MENU_ITEM_TYPE_END_OF_MENU, "", 0}};
void main() {
_fptr temp;
temp = MainMenu[1].FunctionPntr;
(*temp)();
}
void Test(void) {
printf("Hello World\n\r");
printf("%s",MainMenu[1].Text);
} |
Oh and by the way thanks PCM Programmer for that example on how to use function pointers, was a massive help.
That bit should be ok but seeing as none of table entrys change it would be nice to have it in ROM. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Feb 02, 2009 1:31 pm |
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| Quote: | void main() {
_fptr temp;
temp = MainMenu[1].FunctionPntr;
(*temp)();
while(1);
} |
I added the while(1) statement at the end of main() so it didn't cut off
part of the "Show" text. Then it displayed:
So do you still have a problem, or are you done ? (i.e. it's working OK) |
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Guest
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| Posted: Wed Feb 04, 2009 8:33 am |
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Well there is a small problem with this, if the user selects an entry without a pointer to a function (its supposed to be 0) it crashes.
I have the entry set to 0 so I can check "if (temp != 0) (*temp)();" but it doesn't seem to work correctly as temp gets filled with 0xFF but if I try to check against 0xFF it still crashes.
Change main() to:
| Code: | void main() {
_fptr temp;
temp = MainMenu[2].FunctionPntr;
if (temp != 0) (*temp)();
while(1);
} |
That should illustrate the problem I face now. |
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Wipster
Joined: 09 Oct 2008
Posts: 16
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| Posted: Wed Feb 04, 2009 8:34 am |
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| Woops forgot to sign in, sorry. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Feb 04, 2009 1:18 pm |
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I couldn't duplicate your problem. I took your existing code, as posted
earlier, and changed the main() to match your latest post. Then I added
a printf statement to look at the value of the temp pointer. I got 0.
Example:
| Code: | void main()
{
_fptr temp;
temp = MainMenu[2].FunctionPntr;
printf("temp = %LX", temp); // *** For Testing ***
// if (temp != 0) (*temp)();
while(1);
} |
Can you post a test program that shows the problem consistently ?
Also post your compiler version. If you do those two things I can work on it. |
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Wipster
Joined: 09 Oct 2008
Posts: 16
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| Posted: Fri Feb 06, 2009 2:50 pm |
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Sorry I can't seem to duplicate my problem, I don't know why it's happening - it's pretty much a non issue because all of the entrys in the menu will be linked with something, but in this testing phase I have pointed them to a NULLFunction which does nothing.
Thanks anyway. |
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future_
Guest
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| Posted: Mon Feb 09, 2009 4:49 pm |
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Hi,
Does this code compile/work on ccs version 3.249?
This version could not find the function addresses last time I tried to initialize structs with pointers to function.
Thank you. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Feb 09, 2009 5:01 pm |
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The code posted in this thread won't compile in vs. 3.249. The code
in my link compiles, but it gives an error in the MPLAB simulator.
So either vs. 3.249 is too early for function pointers to work properly,
or it would take some research to find work-arounds. |
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