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Real time clock with ST7 Timer Output Compare

3.1 HARDWARE CONFIGURATION

The real time clock application hardware is made of a ST72324 microcontroller timer which

generates a 100ms time base through the Timer B Output Compare 1 function . Two of the

software counters (seconds and minutes) are output by the microcontoller through I/O ports

(PC, PF and PD) and displayed on LEDs as shown in Figure 3. The Seconds counter is shown

with a red LED and the Minutes counter is shown with a pink LED.

the PLL is disabled and slow mode is not selected.

Figure 3. Real Time Clock Application

The RTC accuracy depends on the clock source (e.g. Resonator Oscillator) accuracy. Care

should be taken especially for time critical applications.

TIMER

OC registers

ST72324

RAM

sw counter

SOFTWARE

I/O

PORTS

PD0

LED

LED

LED