Yes, your syntax is indeed correct. The
| operator is the bitwise OR operator in C and C++, and it's used to set a specific bit in a byte. Here's a breakdown of what your line of code does:
EEPROM.read(0) reads the current value of the first byte in the EEPROM.
0x20 is the hexadecimal representation of 32, which is
00100000 in binary. This means that the fifth bit (counting from zero) is set to 1, and all other bits are set to 0.
EEPROM.read(0) | 0x20 performs a bitwise OR operation on the current value of the first byte in the EEPROM and
0x20. This will set the fifth bit of the byte to 1, and leave the other bits unchanged.
EEPROM.update(0, EEPROM.read(0) | 0x20) updates the first byte in the EEPROM with the new value.
So, your approach to set a specific bit in an EEPROM byte is correct.
Here's a more detailed example:
byte bitToSet = 5; // Bit number to set (0-7)
byte eepromAddress = 0; // EEPROM address (0-1023 for ATmega328)
// Read current value
byte currentValue = EEPROM.read(eepromAddress);
// Create mask for bit to set
byte mask = 1 << bitToSet;
// Update value
byte newValue = currentValue | mask;
// Write updated value back to EEPROM
It's worth noting that the
EEPROM.update() function is smart enough to only perform a write if the new value is different from the old one. This is important because the EEPROM has a limited number of write cycles. So using
EEPROM.update() instead of
EEPROM.write() can help extend the life of the EEPROM.