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= Arduino Memory =
 * [[Arduino]] has very littel memory, the uno only 2kbyte of ram.
 * I had sketch hang/crash without any warning, and it was due to lack of memory(ram)
   * check with $avr-size on the compiled elf file, under /tmp/build?????/*.elf
   * Solution
     * Move debug strings to to flash with PROGMEM or macro PSTR

 * Nice solution from http://www.utopiamechanicus.com/399/low-memory-serial-print/
{{{
#include <avr/pgmspace.h>
 
int freeRam () {
  extern int __heap_start, *__brkval;
  int v;
  return (int) &v - (__brkval == 0 ? (int) &__heap_start : (int) __brkval);
}
 
void StreamPrint_progmem(Print &out,PGM_P format,...)
{
  // program memory version of printf - copy of format string and result share a buffer
  // so as to avoid too much memory use
  char formatString[128], *ptr;
  strncpy_P( formatString, format, sizeof(formatString) ); // copy in from program mem
  // null terminate - leave last char since we might need it in worst case for result's \0
  formatString[ sizeof(formatString)-2 ]='\0';
  ptr=&formatString[ strlen(formatString)+1 ]; // our result buffer...
  va_list args;
  va_start (args,format);
  vsnprintf(ptr, sizeof(formatString)-1-strlen(formatString), formatString, args );
  va_end (args);
  formatString[ sizeof(formatString)-1 ]='\0';
  out.print(ptr);
}
 
#define Serialprint(format, ...) StreamPrint_progmem(Serial,PSTR(format),##__VA_ARGS__)
#define Streamprint(stream,format, ...) StreamPrint_progmem(stream,PSTR(format),##__VA_ARGS__)
 
void setup()
{
  Serial.begin(9600);
  Serial.print("12345678901234567890123456789012345678901234567890");
  Serialprint("");
  Serialprint(" memory available: %d bytes\n",freeRam());
}
void loop()
{
}



}}}
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CategoryElectronics