Stuck when verifying card-embed

[Hans-Wu-cn]

When I verify based on this document[ https://jzow.github.io/discovery/microbit/03-setup/verify.html#%E9%AA%8C%E8%AF%81cargo -Embedded], enter

$rustup target add thumbv7em-none-eabihf
$ cargo embed --target thumbv7em-none-eabihf

out:

[hans@MiWiFi-RA72-srv led_roulette]$ cargo embed --target thumbv7em-none-eabihf
    Finished dev [unoptimized + debuginfo] target(s) in 0.16s
      Config default
      Target /home/hans/文档/microbit/led_roulette/target/thumbv7em-none-eabihf/debug/rtt-check
     Erasing sectors ✔ [00:00:00] [####] 16.00KiB/16.00KiB @ 31.82KiB/s (eta 0s )
 Programming pages   ✔ [00:00:00] [####] 16.00KiB/16.00KiB @  9.66KiB/s (eta 0s )
    Finished flashing in 1.217s

No print Hello World

this is my code:

#![no_std]
#![no_main]

use panic_rtt_target as _;
use rtt_target::{rtt_init_print, rprintln};

use cortex_m_rt::entry;

#[entry]
fn main() -> ! {
    rtt_init_print!();
    rprintln!("Hello World");
    loop {}
}

my rust-analyzer point out ‘#[entry]’ field up of Channels is private

[arr-ee]

my rust-analyzer point out ‘#[entry]’ field up of Channels is private

This is a red herring: rust-lang/rust-analyzer#14047. I see this error as well, but it does not prevent the program from working.