🛠 Sommeil profond et réveil programmé ou sur broche

Objectives

Powering the Pico 2 W on battery requires sleeping: putting the RP2350 to sleep between readings, waking it at fixed times using hardware alarms (1 timer + 4 alarms) or on a GPIO edge, and measuring the gain. Note: the CYW43 must turn off its radio part, and the specific currents for the Pico 2 W (including radio) are not published in the datasheet.

Hardware

• Pico 2 W powered via VSYS (LiPo battery via the documented charger pattern)
• Button on GP15 for wake-up on edge
• pico-sdk (header pico/sleep.h)

Complete code

// main.c - cycle : reveil -> releve -> dormant -> alarme 30 s plus tard
#include "pico/stdlib.h"
#include "pico/sleep.h"

#define BOUTON_REVEIL 15

int main(void) {
    stdio_init_all;
    sleep_init_runsleep_and_sleep_mode(
        SLEEP_MODE_DORMANT,
        WAKE_ON_GPIO | WAKE_ON_ALARM_0 | WAKE_ON_RP2350_DORMANT_WAKEUP_SOURCE_GPIO);
    gpio_init(BOUTON_REVEIL);
    gpio_set_dir(BOUTON_REVEIL, GPIO_IN);
    gpio_pull_up(BOUTON_REVEIL);
    while (true) {
        printf("Releve : je travaille\n");   // tache utile ici
        sleep_run_when_both_cores;          // les deux coeurs doivent dormir
        sleep_goto_dormant_until_timer_alarm_absolute(
            make_timeout_time_ms(30000));     // ou : bouton sur GP15
        printf("Reveille !\n");
    }
}

Expected verification

The board prints a Reading every 30 seconds in alarm mode, and immediately when pressing GP15 in GPIO wake-up mode. An ammeter in series with the battery shows a clear drop in current during sleep (Pico 2 P1.x order of magnitude: 148-233 microamperes, radio off).

Common errors

• Forgetting to put BOTH cores to sleep (sleep_run_when_both_cores on RP2350): the board never truly sleeps.
• Leaving the CYW43 powered and connected to Wi-Fi: the radio consumes power in beaconing mode; turn off cyw43_arch before sleeping.
• Reading VSYS (GP29) upon wake-up while the radio is resuming: the line is shared with the CYW43 SPI; give priority using cyw43_thread_enter/exit.
• Waiting for printf while sleeping: the serial console is cut off; prepare a flag to be printed upon wake-up.