AN3133 datasheet(30/43 Pages) STMICROELECTRONICS

Part #	AN3133

Description	A real-time clock is a computer clock that keeps track of the current time

PDF	43 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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30 / 43 page

Application examples

AN3133

30/43

Doc ID 16956 Rev 5

Figure 14.

Calendar example: main program flowchart

These steps are added to have a secure display on the LCD (which uses SPI connections).

Figure 15.

Calendar example: RTC alarm ISR flowchart

Disable interrupts(1)

Enable Interrupts(1)

Enab le RTC clock ( = L SE)

Init the Calendar and the

alarm and enable the Alarm

interrupt

Display Time and Date on

the LCD

START Main Program

Init the LCD and clear it

Config IOs for Leds, Key and

Joystick Buttons and

Enable 3 EXTI Interrupts

(Key, Left_Joy, Right_Joy)

Alarm _Occurred

False

Display Time, Alarm message

on the LCD and Toggle Leds

True

Alarm Occu rr ed = F alse

ai17270

Clear Alarm interrupt pending bit

Return to the Main program

RTC Interrupt Routine

Alarm Occurred = True

ai17271

AN3133 Datasheet(PDF) 30 Page - STMicroelectronics