Which PINs are used for flashing and communication on the Vela IF820?

Vela IF820

Answer

The Vela IF820 can only be flashed using the pins labeled BT_UART_TXD, BT_UART_RXD, BT_UART_CTS, and BT_UART_RTS. These pins are the module’s HCI UART (UART0) and are used for both firmware programming and HCI operation.

  • Flashing is always done via the HCI UART (BT_UART_xxx pins).

    • Flow control (RTS/CTS) is mandatory.

    • The RESET line must also be connected.

    • To enter programming mode, CTS must be held low during reset.

    • Default flashing UART settings: 115200, 8N1.

  • Runtime behavior depends on the firmware loaded:

    • With HCI firmware, the HCI UART continues to carry the standard Bluetooth HCI protocol to the host.

    • With EZ-Serial firmware, the PUART (secondary UART) is used for the EZ-Serial API, but firmware updates are still performed via the HCI UART.