It can run directly from XOSC at MHz 12 (getting lower doesn't spectacularly cuts current draw down):
Above can blink an LED for example. So turning off input buffers (on pads not used as an input), rosc (it is not from SDK, but rather that playground or extras thing) and plls, turning down peripherals and clocks for unused stuff like memory banks etc and SSI controller if there is an option to run from flash.
About RTC and stuff, there is an official document called Power-switching-RP2040-for-low-standby-current-applications.pdf. Removing Pico's (2)(W) SMPS enable pull and you can control power IC externally and having it pulled from GPIO. But requires hacking hardware obviously.
PS. Awww, katak255 was first with that![:D]( "Very Happy")
Code:
#include "pico/stdlib.h"#include "pico/bootrom.h"#include "pico/sync.h"#include "hardware/pll.h"#include "hardware/rosc.h"#include "hardware/vreg.h"#include "hardware/xosc.h"#include "hardware/clocks.h"#if PICO_RP2040#include "hardware/structs/ssi.h"#endif#include "hardware/structs/xip_ctrl.h"#include "hardware/structs/syscfg.h"#include "hardware/structs/scb.h"int main(void) {...#if !PICO_RP2350A for (uint8_t i = 0; i < 48; i++) {#else for (uint8_t i = 0; i < 30; i++) {#endif gpio_disable_pulls(i); gpio_set_input_enabled(i, 0); gpio_set_input_hysteresis_enabled(i, 0); gpio_set_drive_strength(i, GPIO_DRIVE_STRENGTH_2MA); } clock_configure(clk_ref, CLOCKS_CLK_REF_CTRL_SRC_VALUE_XOSC_CLKSRC, 0, 12 * MHZ, 12 * MHZ); clock_configure(clk_sys, CLOCKS_CLK_SYS_CTRL_SRC_VALUE_CLK_REF, 0, 12 * MHZ, 12 * MHZ); #if PICO_RP2040 vreg_set_voltage(VREG_VOLTAGE_0_95);#else vreg_set_voltage(VREG_VOLTAGE_1_00);#endif clock_stop(clk_adc); clock_stop(clk_usb);#if PICO_RP2040 clock_stop(clk_rtc);#else clock_stop(clk_hstx);#endif clock_stop(clk_peri); pll_deinit(pll_usb); pll_deinit(pll_sys); rosc_disable(); #if PICO_RP2040 xip_ctrl_hw->ctrl = 0b1010; ssi_hw->ssienr = 0; scb_hw->scr |= M0PLUS_SCR_SLEEPDEEP_BITS; clocks_hw->wake_en0 = 0b11110000100010000000100100011001; clocks_hw->wake_en1 = 0b000000000100011; clocks_hw->sleep_en0 = 0b00000000000000000000000100000001; clocks_hw->sleep_en1 = 0b000000000100000;#else scb_hw->scr |= M33_SCR_SLEEPDEEP_BITS; xip_ctrl_hw->ctrl |= 0b00000000000000000000000000001000; clocks_hw->sleep_en0 = 0b00000000100000000000000000000000; clocks_hw->sleep_en1 = 0b00000000000000000000000000000000; clocks_hw->wake_en0 = 0b10001001100000000000000000000000; clocks_hw->wake_en1 = 0b00000000001010000011000011110000;#endif...}About RTC and stuff, there is an official document called Power-switching-RP2040-for-low-standby-current-applications.pdf. Removing Pico's (2)(W) SMPS enable pull and you can control power IC externally and having it pulled from GPIO. But requires hacking hardware obviously.
PS. Awww, katak255 was first with that
Statistics: Posted by MatSOBDev2 — Sun Dec 14, 2025 2:21 pm