7.5 UART Debug Interface

The ATWILC3000A provides Universal Asynchronous Receiver/Transmitter (UART) interfaces for serial communication in both IEEE 802.11 and Bluetooth subsystems.

  • The Bluetooth subsystem has one 4-pin UART interface (BT UART), which can be used for control and data transfer.

  • The IEEE 802.11 subsystem has one 2-pin UART interface (Wi-Fi UART), which can be used for debugging.

The UART interfaces are compatible with the RS-232 standard, where the ATWILC3000A operates as a Data Terminal Equipment (DTE) type device. The 2-pin UART uses receive and transmit pins (RXD and TXD). The 4-pin UART uses two pins for data (TXD and RXD) and two pins for flow control/handshaking: Request-to-Send (RTS) and Clear-to-Send (CTS).

Bluetooth UART is available in pins #14 (BT_TXD), #15 (BT_RXD), #16 (BT_RTS) and #17 (BT_CTS). Wi-Fi UART is available in pins #22 (UART_TXD) and #23 (UART_RXD). The following is the default configuration for the Wi-Fi UART interface of the ATWILC3000A:
  • Baud rate: 115200
  • Data: 8-bit
  • Parity: None
  • Stop bit: 1-bit
  • Flow control: None
Important: The UART RTS and UART CTS pins are used for hardware flow control. These pins must be connected to the Host MCU UART and enabled for the UART interface to be functional.

An example of UART receiving or transmitting a single packet is shown in following figure. This example shows 7-bit data (0x45), odd parity and two Stop bits.

Figure 7-3. Example of UART Rx or Tx Packet