FAP's keyboard interrupt controller

int_ctrl.c

int main(void)
{
  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();
  /* Configure the system clock */
  SystemClock_Config();
  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_USART1_UART_Init();
  MX_USART3_UART_Init();

  HAL_UART_MspInit(&huart1);
  HAL_UART_MspInit(&huart3);

  // turn off keyboard data latch
  HAL_GPIO_WritePin(PORT_CTRL_PORT, KB_LATCH_H, LOW);
  // deselect keyboard interrupt
  HAL_GPIO_WritePin(PORT_CTRL_PORT, KB_INT_SEL_L, HIGH);
  // deselect Z80 global interrupt
  HAL_GPIO_WritePin(PORT_CTRL_PORT, GLOBAL_INT_L, HIGH);
  // start receiving data from keyboard
  HAL_UART_Receive_IT(&huart1, kb_recv_buf, RECV_BUF_SIZE);

  while (1)
  {
  	;
  }

}

// UART receive complete
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
  // if we received a byte from keyboard...
  if(huart->Instance==USART1)
  {
    // latch keyboard data
    CPU_DATA_PORT->ODR = kb_recv_buf[0];
    HAL_GPIO_WritePin(PORT_CTRL_PORT, KB_LATCH_H, HIGH);
    // select keyboard interrupt
    HAL_GPIO_WritePin(PORT_CTRL_PORT, KB_INT_SEL_L, LOW);
    HAL_GPIO_WritePin(PORT_CTRL_PORT, GLOBAL_INT_L, LOW);
    HAL_UART_Receive_IT(huart, kb_recv_buf, RECV_BUF_SIZE);
  }
}

// INTACK interrupt handler, rising edge
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
{
  // when CPU's INTACK' goes from active to inactive...
  if(GPIO_Pin == GPIO_PIN_6)
  {
    // clear interrupt
    HAL_GPIO_WritePin(PORT_CTRL_PORT, GLOBAL_INT_L, HIGH);
    HAL_GPIO_WritePin(PORT_CTRL_PORT, KB_INT_SEL_L, HIGH);
    // turn off latch
    HAL_GPIO_WritePin(PORT_CTRL_PORT, KB_LATCH_H, LOW);
  }
}