void Init8LED(void)
{
  if (!(RCC->APB2ENR & RCC_APB2ENR_IOPEEN))
  {
    RCC->APB2ENR |= RCC_APB2ENR_IOPEEN;
    RCC->APB2RSTR |= RCC_APB2RSTR_IOPERST;
    RCC->APB2RSTR &= ~RCC_APB2RSTR_IOPERST;
  }

  GPIOE->CRH = 0x33333333;          // 0011
}

void Write8LED(uint8_t val)
{
  GPIOE->ODR = (GPIOE->ODR & 0x00ff) | (val << 8);
}