Macro register 

macro_rules! register {
    ($uart: ident, $tx_pin: ident, $rx_pin: ident, $baud: expr, $idle_func: expr) => { ... };
    ($uart: ident, $tx_pin: ident, $rx_pin: ident, $baud: expr) => { ... };
}

Registers the UART panic handler.

Arguments

• uart: A peripheral defined in imxrt_ral::lpuart.
• tx_pin: The UART tx pin. Usually defined in the bsp, such as teensy4_bsp::pins::common.
• rx_pin: The UART rx pin. Usually defined in the bsp, such as teensy4_bsp::pins::common.
• baud: The UART baud rate. Most common ones are 9600 and 115200.
• idle_func: Optional. Specifies what function to enter in the end. Default is cortex_m::asm::udf, but this could for example be used to enter teensy4_panic::sos.