static void uart_isr(const struct device *unused, void *user_data)
{
  static slip_t slip = { .state = SLIP_STATE_DECODING,
                         .p_buffer = slip_buffer,
                         .current_index = 0,
                         .buffer_len = sizeof(slip_buffer) 
                       };
  uint8_t byte=0;
  int ret_code=0;


  ARG_UNUSED(unused);
  ARG_UNUSED(user_data);

  while (uart_irq_update(uart_dev) && uart_irq_is_pending(uart_dev)) 
  {
    if (!uart_irq_rx_ready(uart_dev)) 
    {
        if (uart_irq_tx_ready(uart_dev)) {
                printk("transmit ready\n");
        } else {
                printk("spurious interrupt\n");
        }
        // Only the UART RX path is interrupt-enabled 
        break;
    }


    uart_fifo_read(uart_dev, &byte, sizeof(byte));
    ret_code = slip_decode_add_byte(&slip, byte);

    switch (ret_code) 
    {
      case UART_PACKET_RECIEVED_SUCCESS: 
      {
        uint16_t checksum_local = crc16_ansi(slip.p_buffer, slip.current_index - CHECKSUM_SIZE);
        uint16_t checksum_incoming;

        memcpy(&checksum_incoming, slip.p_buffer + (slip.current_index - CHECKSUM_SIZE),  sizeof(checksum_incoming));

        if (checksum_incoming == checksum_local) 
        {
            struct net_buf *buf = net_buf_alloc_len(&uart_pool, slip.current_index - CHECKSUM_SIZE, K_NO_WAIT);
            net_buf_add_mem(buf, slip.p_buffer, slip.current_index - CHECKSUM_SIZE);
            net_buf_put(&tx_queue, buf);
        } 
        else 
        {
            //printk("Invalid Checksum %02x vs %02x\n",checksum_incoming,checksum_local);
            printk("Invalid Checksum x%04x vs x%04x, len=%d\n",checksum_incoming,checksum_local,slip.current_index);
            //buf2hex(slip.p_buffer,slip.current_index);
        }
      }
              // fall through
      case -ENOMEM:
          slip.current_index = 0;
          slip.state = SLIP_STATE_DECODING;
          break;

      default:
          break;
    }
  }
}