OLED FM Radio

#include <Arduino.h>
#include <Wire.h>
#include <U8g2lib.h>
#include <WiFi.h>
#include <time.h>
// Network credentials stay in firmware; never print them.
constexpr char WIFI_SSID[]="TurkTelekom_TP09B0";
constexpr char WIFI_PASSWORD[]="E7DvFUmRWJp9";
char clockText[6]="--:--";
char dateText[11]="--.--.--";
char stationName[9]="";
char psCandidate[9]="        ";
uint8_t psMask=0;
uint16_t stationPI=0;
uint32_t lastRdsPoll=0, rdsResume=0;
void resetRds(){
 stationName[0]=0;memcpy(psCandidate,"        ",9);psMask=0;stationPI=0;
 rdsResume=millis()+250;
}
uint32_t lastClockCheck=0, lastWifiRetry=0;
bool timeConfigured=false;
char clockHeader[16]="WIFI BEKLE";
constexpr int SDA_PIN=0, SCL_PIN=1, RESET_PIN=3;
// Manufacturer example: SSD1306 RAM window x=30..101, y=12..51.
U8G2_SSD1306_128X64_NONAME_F_SW_I2C oled(U8G2_R0,6,5,U8X8_PIN_NONE);
// Si4702/03: SEEKTH (05h.15:8), SKSNR (06h.7:4), SKCNT (06h.3:0).
// Higher values reject more weak/noisy seek candidates.
constexpr uint8_t SEEK_RSSI=10, SEEK_SNR=0, SEEK_IMPULSE=0;
uint16_t regs[16];
int freq=875, volume=1;
bool healthy=true;
bool notFound=false;
bool readRadio(){
 if(Wire.requestFrom((uint8_t)0x10,(uint8_t)32)!=32) return false;
 for(int n=0;n<16;n++){int i=(10+n)%16; regs[i]=(Wire.read()<<8)|Wire.read();}
 return true;
}
bool writeRadio(){
 Wire.beginTransmission(0x10);
 for(int i=2;i<=7;i++){Wire.write(regs[i]>>8);Wire.write(regs[i]&255);}
 return Wire.endTransmission()==0;
}
bool waitSTC(bool state, uint32_t timeout=1500){
 uint32_t start=millis();
 do {if(!readRadio())return false; if(bool(regs[10]&0x4000)==state)return true;delay(2);}while(millis()-start<timeout);
 return false;
}
bool tune(){
 if(!readRadio())return false;
 regs[3]=(regs[3]&0xFC00)|(freq-875)|0x8000;
 if(!writeRadio())return false;
 bool ok=waitSTC(true);
 regs[3]&=~0x8000;
 if(!writeRadio())return false;
 return waitSTC(false)&&ok;
}
// Let the receiver seek internally instead of tuning every channel in software.
bool seekStation(bool upwards){
 notFound=false;
 resetRds();
 if(!readRadio())return false;
 const int previous=freq;
 // Wrap at band edges, choose direction, then start hardware seek.
 regs[2]=(regs[2]&~0x0700)|(upwards?0x0200:0)|0x0100;
 if(!writeRadio())return false;
 bool complete=waitSTC(true,15000);
 bool failed=bool(regs[10]&0x2000);
 int found=875+(regs[11]&0x03FF);
 regs[2]&=~0x0100;
 if(!writeRadio())return false;
 if(!waitSTC(false))return false;
 if(!complete){freq=previous;notFound=true;return tune();}
 freq=found;
 if(failed){notFound=true;freq=previous;return tune();}
 return true;
}
// Maker's drawFrame(30,12,72,40): only this RAM window is visible.
// All layout coordinates below are local to the actual 72x40 panel.
constexpr int SCREEN_X=30, SCREEN_Y=12, SCREEN_W=72, SCREEN_H=40;
// Permanent layout within the visible 72x40 pixels; no rotating pages.
void centeredLine(int baseline,const char *text){
 int width=oled.getStrWidth(text);
 oled.drawStr(SCREEN_X+(SCREEN_W-width)/2,SCREEN_Y+baseline,text);
}
void draw(){
 oled.clearBuffer();
 oled.setFontMode(1);
 oled.setFontPosBaseline();
 char s[24];
 // Small date/time sits immediately above the unchanged frequency.
 oled.setFont(u8g2_font_5x7_tr);
 snprintf(s,sizeof(s),"%s %s",dateText,clockText);
 centeredLine(26,s);
 oled.setFont(u8g2_font_9x15_tr);
 snprintf(s,sizeof(s),"%d.%d",freq/10,freq%10);
 oled.drawStr(SCREEN_X,SCREEN_Y+39,s);
 oled.setFont(u8g2_font_8x13_tr);
 snprintf(s,sizeof(s),"%d",volume);
 oled.drawStr(SCREEN_X+SCREEN_W-oled.getStrWidth(s)-3,SCREEN_Y+39,s);
 oled.drawHLine(SCREEN_X,SCREEN_Y+42,SCREEN_W);
 oled.setFont(u8g2_font_4x6_tr);
 const char *rds=stationName[0]?stationName:"RDS BEKLE";
 if(notFound)rds="BULUNAMADI";
 if(!healthy)rds="RADYO HATA";
 centeredLine(51,rds);
 oled.sendBuffer();
}
// Standard RDS mode: RDSR exposes corrected complete groups.
// Group 0A/0B carries two PS characters in block D, indexed by B bits 1:0.
void pollRds(){
 if(!healthy || millis()-lastRdsPoll<30 || int32_t(millis()-rdsResume)<0)return;
 lastRdsPoll=millis();
 if(!readRadio() || !(regs[10]&0x8000))return;
 if((regs[13]>>12)!=0)return;
 if(stationPI!=regs[12]){
 stationPI=regs[12];psMask=0;memcpy(psCandidate,"        ",9);
 }
 int segment=regs[13]&3;
 char first=regs[15]>>8,second=regs[15]&255;
 // Use printable characters supported by the small display font.
 if((uint8_t)first<32 || (uint8_t)first>126)first='?';
 if((uint8_t)second<32 || (uint8_t)second>126)second='?';
 psCandidate[segment*2]=first;psCandidate[segment*2+1]=second;
 psMask|=1<<segment;
 if(psMask==15){
 if(strcmp(stationName,psCandidate)!=0){memcpy(stationName,psCandidate,9);draw();}
 psMask=0;
 }
}
struct Button{int pin;bool raw=HIGH,stable=HIGH;uint32_t changed=0;};
Button bootButton{9};
uint32_t pressedAt=0, releasedAt=0;
bool longHandled=false, pendingClick=false;
void changeVolume(int delta){
 notFound=false;volume=constrain(volume+delta,0,15);
 healthy=readRadio();
 if(healthy){regs[5]=(regs[5]&0xFFF0)|volume;healthy=writeRadio();}
 draw();
}
void seekForward(){
 oled.clearBuffer();oled.setFont(u8g2_font_6x10_tr);oled.setFontPosBaseline();
 oled.drawStr(SCREEN_X+9,SCREEN_Y+34,"ARANIYOR");oled.sendBuffer();
 healthy=seekStation(true);rdsResume=millis()+250;draw();
}
void pollButton(){
 uint32_t now=millis();bool level=digitalRead(bootButton.pin);
 if(level!=bootButton.raw){bootButton.raw=level;bootButton.changed=now;}
 if(now-bootButton.changed>=30 && bootButton.stable!=bootButton.raw){
  bootButton.stable=bootButton.raw;
  if(bootButton.stable==LOW){pressedAt=now;longHandled=false;}
  else if(!longHandled){
   if(pendingClick && now-releasedAt<=350){pendingClick=false;seekForward();}
   else {pendingClick=true;releasedAt=now;}
  }
 }
 if(bootButton.stable==LOW && !longHandled && now-pressedAt>=700){
  longHandled=true;pendingClick=false;changeVolume(-1);
 }
 if(pendingClick && bootButton.stable==HIGH && now-releasedAt>350){
  pendingClick=false;changeVolume(1);
 }
}
void setup(){
 pinMode(bootButton.pin,INPUT_PULLUP);
 // External 10k SEN pull-up selects 2-wire mode with SDIO low.
 pinMode(RESET_PIN,OUTPUT);digitalWrite(RESET_PIN,LOW);
 pinMode(SDA_PIN,OUTPUT);digitalWrite(SDA_PIN,LOW);delay(2);
 digitalWrite(RESET_PIN,HIGH);delay(2);
 Wire.begin(SDA_PIN,SCL_PIN);Wire.setClock(100000);Wire.setTimeOut(100);
 healthy=readRadio();
 if(healthy){regs[7]=0x8100;healthy=writeRadio();delay(500);}
 if(healthy){healthy=readRadio();regs[2]=0x4001;regs[4]|=0x1800;
 regs[5]=(uint16_t(SEEK_RSSI)<<8)|0x0010|volume;
 regs[6]=(regs[6]&0xF100)|(uint16_t(SEEK_SNR)<<4)|SEEK_IMPULSE;
 healthy=writeRadio()&&healthy;delay(110);}
 if(healthy){healthy=tune();}
 oled.setBusClock(100000);oled.begin();draw();
 // Nonblocking network connection: radio remains usable without Wi-Fi.
 WiFi.mode(WIFI_STA);WiFi.setAutoReconnect(true);
 WiFi.begin(WIFI_SSID,WIFI_PASSWORD);
 lastWifiRetry=millis();
}
void loop(){
 if(millis()-lastClockCheck>=1000){
 lastClockCheck=millis();
 char nextHeader[16];
 char nextDate[11];strcpy(nextDate,dateText);
 if(WiFi.status()!=WL_CONNECTED){
 snprintf(nextHeader,sizeof(nextHeader),"WIFI YOK");
 if(millis()-lastWifiRetry>=30000){
 lastWifiRetry=millis();WiFi.disconnect();WiFi.begin(WIFI_SSID,WIFI_PASSWORD);
 }
 }else{
 if(!timeConfigured){
 configTime(3*3600,0,"pool.ntp.org","time.google.com","time.cloudflare.com");
 timeConfigured=true;
 }
 time_t now=time(nullptr);
 if(now>1700000000){
 struct tm local;localtime_r(&now,&local);
 strftime(clockText,sizeof(clockText),"%H:%M",&local);
 strftime(nextDate,sizeof(nextDate),"%d.%m.%y",&local);
 snprintf(nextHeader,sizeof(nextHeader),"FM   %s",clockText);
 }else snprintf(nextHeader,sizeof(nextHeader),"SAAT BEKLE");
 }
 if(strcmp(nextHeader,clockHeader)!=0 || strcmp(nextDate,dateText)!=0){
 strcpy(clockHeader,nextHeader);strcpy(dateText,nextDate);draw();
 }
 }
 pollButton();
 pollRds();
 delay(2);
}