STM32 импульсный генератор 1кГц ... 64МГц

#include <Wire.h> 
#include <LiquidCrystal_I2C.h> // liquidcrystali2c.zip
  LiquidCrystal_I2C lcd(0x27,16,2);  // Устанавливаем дисплей
  HardwareTimer pwmtimer3(3);

long int del=1,mn=1;
float f;

void setup() {
  lcd.init();                     
  lcd.backlight();// Включаем подсветку дисплея
  ///////////////////////////
  pinMode(PB0, PWM);
  pinMode(PB1,INPUT); // +
  pinMode(PB10,INPUT);// -
  pinMode(PB11,INPUT);// х1 х10 x100 x1000
  pwmtimer3.pause();
  pwmtimer3.setPrescaleFactor(del);       
  pwmtimer3.setOverflow(2-1);// /2         
  pwmtimer3.setCompare(TIMER_CH3, 1);// меандр
  pwmtimer3.refresh();
  pwmtimer3.resume();
}
void loop() {
    if(digitalRead(PB11)==HIGH){mn=mn*10;if(mn>1000){mn=1;}}
    if(digitalRead(PB1)==HIGH){del=del+mn;if(del>65535){del=65535;}pwmtimer3.setPrescaleFactor(del);}
    if(digitalRead(PB10)==HIGH){del=del-mn;if(del<1){del=1;}pwmtimer3.setPrescaleFactor(del);}
    
  lcd.setCursor(0, 0);
  lcd.print("F = ");
  f = 64000000/(1*del);
  if(f>1000000){lcd.print(f/1000000,3);lcd.print(" MHz   ");}else{lcd.print(f/1000,3);lcd.print(" kHz   ");}
  lcd.setCursor(0,1);
  lcd.print("x");lcd.print(mn);lcd.print("   ");lcd.setCursor(6,1);lcd.print("d");lcd.print(del);lcd.print("      ");
  delay(300);
}