The most suitable application for a round display is a programmable watch.

Using the GFX Library for Arduino (https://github.com/moononournation/Arduino_GFX) , we can easily configure and start using the round LCD, printing text and image on the display and playing animation.

What's best, the AMB23 dev board comes with built-in audio codec and an on-board audio jack for WAV audio data playing, so we can record a voice message and convert it to WAV, put it on the SD card then play the voice message at the designated time.

Here is the code,

/*
   Arduino Watch Lite Version
   You may find full version at: https://github.com/moononournation/ArduinoWatch
*/

/*******************************************************************************
 * Start of Arduino_GFX setting
 * 
 * Arduino_GFX try to find the settings depends on selected board in Arduino IDE
 * Or you can define the display dev kit not in the board list
 * Defalult pin list for non display dev kit:
 * ESP32 various dev board     : TFT_CS:  5, TFT_DC: 27, TFT_RST: 33, TFT_BL: 22
 * ESP8266 various dev board   : TFT_CS: 15, TFT_DC:  4, TFT_RST:  2, TFT_BL:  5
 * RTL872x various dev board   : TFT_CS: 12, TFT_DC: 14, TFT_RST: 15, TFT_BL: 13, VCC: 3V3, GND: GND, SDA: MOSI, SCL: CLK
 * Go to Arduino_GFX_Library.h and update the TFT misc pins according to the definitions listed below
 * #elif defined(RTL8722DM)
   #define TFT_CS 12 
   #define TFT_DC 14
   #define TFT_RST 15
   #define TFT_BL 13
 * Arduino Nano, Micro and more: TFT_CS:  9, TFT_DC:  8, TFT_RST:  7, TFT_BL:  6
 ******************************************************************************/
#include <Arduino_GFX_Library.h>

/* More dev device declaration: https://github.com/moononournation/Arduino_GFX/wiki/Dev-Device-Declaration */
#if defined(DISPLAY_DEV_KIT)
Arduino_GFX *gfx = create_default_Arduino_GFX();
#else /* !defined(DISPLAY_DEV_KIT) */

/* More data bus class: https://github.com/moononournation/Arduino_GFX/wiki/Data-Bus-Class */
Arduino_DataBus *bus = create_default_Arduino_DataBus();

/* More display class: https://github.com/moononournation/Arduino_GFX/wiki/Display-Class */
//Arduino_GFX *gfx = new Arduino_ILI9341(bus, TFT_RST, 0 /* rotation */);
Arduino_GFX *gfx = new Arduino_GC9A01(bus, 15 /* RST */, 0 /* rotation */, true /* IPS */);

#endif /* !defined(DISPLAY_DEV_KIT) */
/*******************************************************************************
 * End of Arduino_GFX setting
 ******************************************************************************/

#define BACKGROUND BLACK
#define MARK_COLOR WHITE
#define SUBMARK_COLOR DARKGREY // LIGHTGREY
#define HOUR_COLOR WHITE
#define MINUTE_COLOR BLUE // LIGHTGREY
#define SECOND_COLOR RED

#define SIXTIETH 0.016666667
#define TWELFTH 0.08333333
#define SIXTIETH_RADIAN 0.10471976
#define TWELFTH_RADIAN 0.52359878
#define RIGHT_ANGLE_RADIAN 1.5707963


/////////////////// Audio Setting ////////////////////////

#include "FatFs_SD.h"
#include "PlaybackWav.h"
#include "AudioCodec.h"

char filename[] = "Time_Audio_16khz_16bit_Mono.wav";

#define BUFFERSIZE 512
int16_t buffer[BUFFERSIZE] = {0};

FatFsSD fs;
PlaybackWav playWav;


// Callback function to feed audio codec with additional data
void writeCBFunc() {
    if(Codec.writeAvaliable()) {
        playWav.readAudioData(buffer, BUFFERSIZE);
        Codec.writeDataPage(buffer, BUFFERSIZE);
    }
}
int playWavTime;
//////////////////////////////////////////////////////////


static uint8_t conv2d(const char *p)
{
    uint8_t v = 0;
    return (10 * (*p - '0')) + (*++p - '0');
}

static int16_t w, h, center;
static int16_t hHandLen, mHandLen, sHandLen, markLen;
static float sdeg, mdeg, hdeg;
static int16_t osx = 0, osy = 0, omx = 0, omy = 0, ohx = 0, ohy = 0; // Saved H, M, S x & y coords
static int16_t nsx, nsy, nmx, nmy, nhx, nhy;                         // H, M, S x & y coords
static int16_t xMin, yMin, xMax, yMax;                               // redraw range
static int16_t hh, mm, ss;
static unsigned long targetTime; // next action time

static int16_t *cached_points;
static uint16_t cached_points_idx...