I store some data in progmem as it takes up too much space in ram/rom so i created an array of strings and when i call the string out and copy it into another string and print it to serial out i get garbage computer symbols, the line of code i bring the string out of memory is strcpy_P(PrintString, (PGM_P)pgm_read_word(&(StoredString[0])));
thanks
Moved to appropriate forum,
Can you specify the AVR and Toolchain you are using?
Thanks
Jim
Also, provide more context -- ideally, a complete test program that demonstrates your symptoms. Tell what you expect to happen, and what >>is<< happening.
print it to serial out i get garbage computer symbols,
In at least 98% of cases, the reason for "garbage symbols" in UART comms is the wrong baud rate - so check that first.
This seems to work well for flash-based strings:
const char STR001[] PROGMEM = "Example One";
const char STR002[] PROGMEM = "Example Two with more words";
const char STR003[] PROGMEM = "Ex Three";
// Then set up a table to refer to your strings.
PGM_P STR_table[] = {STR001, STR002, STR003};
void setup()
{
Serial.begin(9600);
}
void loop()
{
int i;
char buffer[45];
for (i = 0; i<3; i++) {
strcpy(buffer, (PGM_P) pgm_read_word(&(STR_table[i])));
Serial.println( buffer );
}
}
Why are people still using PROGMEM and pgm_read_word when the compiler now has "__flash" to make all this stuff 10 times easier?
> Why are people still using PROGMEM and pgm_read_word when the compiler
> now has "__flash" to make all this stuff 10 times easier?
Because C++ is so cool.
Isolate your flash data and accesses in a C source file, using the modern __flash stuff. Then call it from C++.
I guess but a real shame the avr-g++ people won't allow their language to be "polluted" with __flash :-(
Yup, but sinse they won't give we can but whine and find a different solution :-)
