Mpu::disable();
Mpu::setRegion(0, 0x00000000, MpuRegSize::_512MB, MpuAttr::Normal_NonShareable_NonCacheable);   // ITCM/Flash/System Memory
Mpu::setRegion(1, 0x20000000, MpuRegSize::_512MB, MpuAttr::Normal_NonShareable_NonCacheable);   // DTCM/AXISRAM/SRAM1234/BackupSram
Mpu::setRegion(2, 0x40000000, MpuRegSize::_512MB, MpuAttr::Device_NonShareable, true);          // Peripheral
Mpu::setRegion(3, 0x60000000, MpuRegSize::_512MB, MpuAttr::Normal_NonShareable_NonCacheable);   // External RAM
Mpu::setRegion(4, 0x80000000, MpuRegSize::_512MB, MpuAttr::Normal_NonShareable_NonCacheable);   // External RAM
Mpu::setRegion(5, 0xC0000000, MpuRegSize::_512MB, MpuAttr::Device_NonShareable, true);          // External Device 
Mpu::setRegion(6, 0xE0000000, MpuRegSize::_1MB,   MpuAttr::Ordered_Shareable, true);            // Private peripheral bus
Mpu::setSubRegions(3, 0b0000'0001, 0x60000000, MpuSRegSize::_16KB, MpuAttr::Normal_NonShareable_WriteBackWriteAllocate);
Mpu::enable();

auto addr = (uint16_t*)0x6000'0000;

for (int i = 0; i < 8192; i += 2)
    addr[i] = 0x1234 + i;

for (int i = 0; i < 8192; i += 2)
{
    if (addr[i] != 0x1234 + i)
        rtt.print<"Error: {}, {x}\n">(i, addr[i]);
}

// Variable bits
bit p_on;
bit p_off;

void main() {
  DDRB = 0x08; // Set PB3 pin as output, other inputs
  p_on = 0;    // Bit initial value
  p_off = 1;   // Bit initial value
  do {
    if (Button(&PINB, 0, 1, 1)) {   // Detect logical one
      p_on = 1;                     // Update flag
    }
    if (p_on == 1 && Button(&PINB, 0, 1, 0)) { // Detect one-to-zero transition
      p_on = 0;                     // Update flag
    }
    if (p_on == 1 && p_off == 1) {  // Switching on
      PORTB3_bit = 1;               // Set PB3 pin = 1
      Delay_ms(300);                // Wait for a while
      PORTB3_bit = 0;               // Set PB3 pin = 0
      p_off = 0;                    // Update flag
      Delay_ms(100);                // Wait for a while
    }
    if (p_on == 0 && p_off == 0) {  // Switching off
      PORTB3_bit = 1;               // Set PB3 pin = 1
      Delay_ms(300);                // Wait for a while
      PORTB3_bit = 0;               // Set PB3 pin = 0
      p_off = 1;                    // Update flag
      Delay_ms(100);                // Wait for a while
    }
  } while(1);                       // Endless loop
}