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progmem.ino
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progmem.ino
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/*
PROGMEM string demo
How to store a table of strings in program memory (flash),
and retrieve them.
Information summarized from:
http://www.nongnu.org/avr-libc/user-manual/pgmspace.html
Setting up a table (array) of strings in program memory is slightly complicated, but
here is a good template to follow.
Setting up the strings is a two-step process. First define the strings.
*/
#include <avr/pgmspace.h>
prog_char string_0[] PROGMEM = "String 0"; // "String 0" etc are strings to store - change to suit.
prog_char string_1[] PROGMEM = "String 1";
prog_char string_2[] PROGMEM = "String 2";
prog_char string_3[] PROGMEM = "String 3";
prog_char string_4[] PROGMEM = "String 4";
prog_char string_5[] PROGMEM = "String 5";
// Then set up a table to refer to your strings.
PROGMEM const char *string_table[] = // change "string_table" name to suit
{
string_0,
string_1,
string_2,
string_3,
string_4,
string_5 };
char buffer[30]; // make sure this is large enough for the largest string it must hold
void setup()
{
Serial.begin(9600);
}
void loop()
{
/* Using the string table in program memory requires the use of special functions to retrieve the data.
The strcpy_P function copies a string from program space to a string in RAM ("buffer").
Make sure your receiving string in RAM is large enough to hold whatever
you are retrieving from program space. */
for (int i = 0; i < 6; i++)
{
strcpy_P(buffer, (char*)pgm_read_word(&(string_table[i]))); // Necessary casts and dereferencing, just copy.
Serial.println( buffer );
delay( 500 );
}
}