Before revision: The real time clock is omitted either out of the desire to save money (as in the Raspberry Pi system architecture ) or because real time clocks may not be needed at all (as in the Arduino system architectureHowever, note that many Arduino software suites include an optional software RTC run from a low precision timer as described.).
After revision: before Raspberry Pi 5The real time clock is omitted either out of the desire to save money (as in the Raspberry Pi system architecture ) or because real time clocks may not be needed at all (as in the Arduino system architectureHowever, note that many Arduino software suites include an optional software RTC run from a low precision timer as described.).