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Implementing Table Read and Write in PIC18F4550

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bliscar

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Hi,
Anyone knows here how to implement Table Read and Write in PIC18F4550 using MPLAB-X or MPLAB IDE as the environment and C18 Compiler...
 

you need to use the 'rom' attribute while defining your pointer and #pragma romdata if it's a table...

for example a table in flash memory (two examples, one table at 0x5000 and other at 0x5200):
Code: 
#pragma romdata PRODS=0x5000
rom int Productos[]= {70,50,50,100,100,150,20,50,60};

#pragma romdata PRODS2=0x5200
rom char Prods[][2]={
{0,0x01},
{1,0x02},
{2,0x03},
{3,0x01},
{3,0x02},
{4,0x02},
{4,0x03},
{5,0x01},
{5,0x02},
{5,0x03},
{6,0x80},
{7,0x80},
{7,0x80},
{7,0x80},
{8,0x80},
{8,0x80},
{8,0x80},
{8,0x80}};

//to finnish pragma code!
#pragma code

and use it like a normal table

Code: 
...

sb1 = Prods[3][0];
sb2 = Prods[3][1];
..
//you know, right?



if you need you can define the pointer externally as:
Code: 
extern rom int Productos[];
extern rom char Prods[][2];

if you want a char pointer to any part of the flash memory,
define a pointer
Code: 
rom char* maPointer;

and use it as you need

Code: 
...
maPointer = 0x5000; //points to some part of the memory

bv = (*maPointer); //read address 0x5000 !!!!

maPointer++; //now points to 0x5001;

//etc
...
//and also
...
(*maPointer) = someValue; //prefills page byte, read the datasheet for actual write in memory!!!

it also works with the table version!

Code: 
Prods[10][0]=newValue; //prefills page byte, again please read the datasheet for actual write... even it's more complicated with a table... do it with a known pointer
 
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