The Arduino atoi() function is not working as expected. The original is 656649, but when converted to a string, it prints 1289. What could be happening? Thanks!
void setup() {Serial.begin(9600);}void loop() {String BT1 = "656649"Serial.print(" String BT1: ");Serial.print(BT1); // OUTPUT: 656649char charBuf[50];BT1.toCharArray(charBuf, 50) ;Serial.print("Char buff: "); // OUTPUT: 656649Serial.print(charBuf);intBT1 = atoi(charBuf);Serial.print(" intBT1: "); //OUTPUT: 1289Serial.print(intBT1);}Best Answer
The Arduino int and 'unsigned int types are 16-bit values, too small to hold the number you used. You need a long or unsigned long type to hold that value; these are 32 bits long in the ATmega (Arduino) architecture.
Many programming problems with the Arduino stem from these different sizes -- as most personal computer are 64-bit these days, it's easy to forget that the microcontrollers at the heart of the Arduino family are Harvard architecture 8-bit machines with 8-bit registers.