When I was writing about speaker audio I reviewed the Arduino processor’s specs, particular section 28.1, “Absolute Maximum Ratings”. For example:
- 6.0v for the chip
- 40mA per I/O pin
- Maximum total current of 200mA (“DC Current VCC and GND Pins”)
Sounds good – then I read the fine print:
Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
So not only was exceeding these values bad, but staying at them for extended periods of time was bad as well!
So I now understood why many sites mentioned much lower values for each pin and total pins (20mA and 100mA, respectively), and also why we work with 5.0v on the Arduino – why go too close to the sun and pull an Icarus with our fragile CPU?
So from now on I’m aiming lower: 20mA per I/O pin, 100mA total, and you likely won’t hear of overclocking to 20mhz or pumping up the voltage anywhere on this blog.
I’ll be good – I promise.
