RTC Program Code

[last updated: 2024-08-06]
PCF8523 programming protocols
RTC - PCF8523
-----

      Generic code for 8523 with 128x32 OLED:

```cpp

// EDIT THIS LINE ********************************
String programName = "RTC_01";

long baudRateSerial = 57600;
// -------------------------------------
//
// Purpose:
// this program shows the minimum code needed
// to write text to an OLED display
//
// Edit History:
// rev. 01: from OLED_minimum_02.ino
// adding hardware for PCF8523 RTC
// libraries added, RTC declaration and rtc.adjust working
// big bold font installed and working
// hrs & mins extracted and displayed on OLED
//
// Program operation/flow:
// ...
//
//
// Hardware configuration:
// 13 onboard LED
// A4 to OLED-SDA
// A5 to OLED-SCL
// gnd and 3.3v connected from Uno to OLED
//
// RTC: PCF8523
// RTC gnd connected to MCU gnd
// RTC Vcc connected to +5v from Nano
// RTC SDA connected to A4 of Nano
// RTC SCL connected to A5 of Nano
// ---------------------------------

// ************** INCLUDES *******************

//#include // this is not needed for text, but IS needed for any graphics
#include // this is the minimum required library
#include

#include

// ---------- END includes ------------

// ************** GLOBALS *******************

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 32 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET 4 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

RTC_PCF8523 rtc;

String textToPrint = "init";
String strHrNow;
String strMinNow;

// ---------------- END globals -----------------

// ************** SETUP *******************

void setup() {

Serial.begin (baudRateSerial);
printPreamble();

// for RTC
if (! rtc.begin()) {
Serial.println("Couldn't find RTC");
Serial.flush();
while (1) delay(10);
}

delay(2000); // wait for RTC to initialize
if (! rtc.initialized() || rtc.lostPower()) {
Serial.println("RTC is NOT initialized, let's set the time!");
rtc.adjust(DateTime(2024, 8, 5, 7, 5, 0)); // rtc.adjust(DateTime(yyyy, mo, day, hr, min, sec))
}

//rtc.adjust(DateTime(2024, 8, 5, 21, 6, 0));

rtc.start();
// ------------------------------------------

// for OLED
if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3C for 128x32
Serial.println(F("SSD1306 allocation failed"));
for(;;); // Don't proceed, loop forever
}

// Clear the buffer
display.clearDisplay();
// draw border
display.drawRect(0, 0, 128, 32, SSD1306_WHITE);
display.display();

// set text parameters
display.setFont(&FreeSansBold18pt7b);
display.setTextColor(WHITE);
display.setCursor(3, 25); // y=6 centers text-size-3 vertically in screen
display.setTextSize(1);

display.print("init...");
display.display();

delay(1500);

} // -------------- END setup --------------

// ************** LOOP *******************

void loop() {

clrCtr();

delay(1500);

DateTime now = rtc.now();

uint16_t yrNow = now.year();
uint16_t hrNow = now.hour();
uint16_t minNow = now.minute();

if (hrNow < 10) {
strHrNow = "0" + String(hrNow);
} else {
strHrNow = String(hrNow);
}
if (minNow < 10) {
strMinNow = "0" + String(minNow);
} else {
strMinNow = String(minNow);
}

textToPrint = strHrNow + ":" + strMinNow;

display.setCursor(20, 27);
display.setTextSize(1);
clrCtr();
// print to OLED
display.print(textToPrint);
display.display();
delay(2000);

} // --------------- END loop ---------------

// **************** FUNCTION DEFS *****************

// list of function defs:

// printPreamble
// clrCtr
// --------------------------

void printPreamble() {

delay(100);
Serial.println(" "); Serial.println(" ---------- ");
Serial.print("Program name: "); Serial.println(programName);
Serial.println(" ---------- ");

} // ---------------- END printPreamble ----------------

void clrCtr() {
display.fillRect(1, 1, 126, 30, BLACK); // clear center of screen
} // ----------------- END clrCtr ----------------------

// --------------- END function defs ------------

// --------------- END program ------------------

```

-------------------------------------------------------------

.

eof