10.5 UART Interface

The ATWILC3000-MR110xA module provides Universal Asynchronous Receiver/Transmitter (UART) interfaces for serial communication in both IEEE 802.11 and Bluetooth subsystems.

  • The Bluetooth subsystem has one UART interface: a 4-pin interface for control and data transfer (BT UART).
  • The IEEE 802.11 subsystem has one 2-pin UART interface (Wi-Fi UART) that can be used for debugging.

The UART interfaces are compatible with the RS-232 standard, and the ATWILC3000-MR110xA module 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 module pins 8 (BT_TXD), 9 (BT_RXD), 10 (BT_RTS) and 11 (BT_CTS). Wi-Fi UART is available in module pins 16 (UART_TXD) and 17 (UART_RXD).

The following is the default configuration for the Wi-Fi UART interface of the ATWILC3000-MR110xA:

  • Baud rate: 115200
  • Data: 8-bit
  • Parity: None
  • Stop bit: 1-bit
  • Flow control: None
Important: The RTS and CTS pins of BT UART are used for hardware flow control. These pins must be connected to the Host MCU UART and could be optionally enabled.

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

Figure 10-3. Example of UART RX or TX Packet