fn rtc_sleep_pu() {
    let rtc_cntl = LPWR::regs();
    let apb_ctrl = APB_CTRL::regs();

    rtc_cntl.dig_pwc().modify(|_, w| {
        w.lslp_mem_force_pu().clear_bit();
        w.fastmem_force_lpu().clear_bit()
    });

    apb_ctrl.front_end_mem_pd().modify(|_, w| {
        w.dc_mem_force_pu().clear_bit();
        w.pbus_mem_force_pu().clear_bit();
        w.agc_mem_force_pu().clear_bit()
    });
    apb_ctrl.mem_power_up().modify(|_, w| unsafe {
        w.sram_power_up().bits(0u8);
        w.rom_power_up().bits(0u8)
    });
}
Configure whether certain peripherals are powered down in deep sleep
esp-hal/src/rtc_cntl/rtc/esp32c3.rs