Are my arrays stored in sram or in Flash?

Question

I have the following memory allocation:

unsigned char g1[]={
 0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ....0x00 ,0x00 ,0x00 ,0x00 ,0x00 }; 
g2[]={
 0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ....0x00 ,0x00 ,0x00 ,0x00 ,0x00 }; 
... 
 unsigned char* index[10] = {g1,g2,g3,g4,g5,g6,g7,g8,g9,g0}; 

This is accessed in the following way:

unsigned char* getMatch(int input){
 return index[input];
}

This is then futher acces using the method of

unsigned char store[1024]
unsigned char* temp = getMatch(n);
for(int i=0;i <50;i++){
 store[i]=temp[i];
}

and store is then modified and send to an external device.

As my program is randomly failing I think it might be running low on SRAM and was wondering if there is any way to force this memory to be placed in flash. Anybody got an idea?

Answer 1

It's stored in both the FLASH and SRAM because it's initialized array. To store in FLASH only you need use PROGMEM attribute.

const unsigned PROGMEM char g1[]= ...

You cannot access directly but using memcpy_P() function.

• Thijser: How would I put this in the 2nd array after this? I get a lot of error: invalid conversion from ‘const unsigned char*’ to ‘unsigned char* errors.
• Thijser: Never mind got it.