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cpu/nrf52/Makefile.features

@@ -5,6 +5,8 @@ CPU_CORE = cortex-m4
 endif
 CPU_FAM  = nrf52
 
+USEMODULE += pm_layered
+
 # The 802.15.4 radio is not available on all SoCs
 ifneq (,$(filter nrf52811xxaa nrf52820xxaa nrf52833xxaa nrf52840xxaa,$(CPU_MODEL)))
   FEATURES_PROVIDED += radio_nrf802154
@@ -34,3 +36,9 @@ ifneq (,$(filter nrf52811% nrf52820% nrf52833% nrf52840%,$(CPU_MODEL)))
 endif
 
 include $(RIOTCPU)/nrf5x_common/Makefile.features
+
+# This configuration enables modules that are only available when using Kconfig
+# module modelling
+ifeq (1, $(TEST_KCONFIG))
+  KCONFIG_ADD_CONFIG += $(RIOTCPU)/nrf52/nrf52.config
+endif

cpu/nrf52/include/periph_cpu.h

@@ -27,6 +27,15 @@
 extern "C" {
 #endif
 
+/**
+ * @name    Power management configuration
+ * @{
+ */
+#define PROVIDES_PM_SET_LOWEST
+#define PROVIDES_PM_RESTART
+#define PROVIDES_PM_OFF
+#define PROVIDES_PM_LAYERED_OFF
+
 /**
  * @brief   Enable the workaround for the SPI single byte transmit errata (No.
  * 58 on the nrf52832)
@@ -269,6 +278,12 @@ void spi_twi_irq_register_i2c(NRF_TWIM_Type *bus,
  */
 #define USBDEV_CPU_DMA_ALIGNMENT       (4)
 
+/**
+ * @brief   Number of usable low power modes
+   FIXME: not sure what is the actual number of modes (see datasheet)
+ */
+#define PM_NUM_MODES            (3U)
+
 /**
  * @brief USBDEV buffer instantiation requirement
  */

cpu/nrf52/nrf52.config

@@ -0,0 +1 @@
+CONFIG_MODULE_PM_LAYERED=y

cpu/nrf52/periph/pm.c

@@ -0,0 +1,91 @@
+#include "periph_cpu.h"
+#include "cpu.h"
+#include "pm_layered.h"
+
+#include "clk.h"
+#include "board.h"
+#include "periph_conf.h"
+#include "timex.h"
+#include "ztimer.h"
+#include "nrf_clock.h"
+#include "ztimer/periph_rtc.h"
+
+#define RTC_FREQ 32768
+#define RTC_INTERVAL 10
+
+void nrf52_sys_on(void) {
+    /* Clear Event Register */
+    __SEV();
+    /* Wait for event */
+    __WFE();
+    /* Wait for event */
+    __WFE();
+}
+
+void RTC1_IRQHandler(void)
+{
+    if(NRF_RTC1->EVENTS_COMPARE[0] == 1) {  
+        NRF_RTC1->EVENTS_COMPARE[0] = 0;
+    } 
+}
+
+// Set the RTC to trigger a wake-up interrupt every 10 second
+void clock_config(void) {
+    // Configure the RTC to use the low-frequency crystal
+    NRF_CLOCK->LFCLKSRC = (CLOCK_LFCLKSRC_SRC_Xtal << CLOCK_LFCLKSRC_SRC_Pos);
+    NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
+    NRF_CLOCK->TASKS_LFCLKSTART = 1;
+
+    // Wait for the low-frequency crystal to start
+    while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0);
+
+}
+void rtc_config(void)
+{ 
+
+    NRF_RTC1->PRESCALER = 0;
+    NRF_RTC1->CC[0] = RTC_INTERVAL * RTC_FREQ;
+
+    NRF_RTC1->INTENSET = RTC_INTENSET_COMPARE0_Msk; // Enable interrupt on compare event 0
+    NRF_RTC1->TASKS_CLEAR = 1;
+    NRF_RTC1->TASKS_START = 1;
+
+}
+
+
+void pm_set(unsigned mode)
+{
+    clock_config();
+    switch (mode) {
+        case 0:
+            //RTC wake up source sleep
+            // Initialize the RTC
+
+            rtc_config();
+            puts("Entering sleep");
+            nrf52_sys_on();
+            RTC1_IRQHandler();
+
+            puts("Exiting sleep");
+            pm_set(1);
+
+        break;
+        case 1:
+            //Ztimer active mode
+            puts("Entering active");
+
+            ztimer_sleep(ZTIMER_MSEC, 10 * MS_PER_SEC);
+
+            pm_set(0);
+
+        break;
+        case 2:
+            //No sleep
+
+        break;
+    }
+}
+
+void pm_off(void);
+
+void pm_set_lowest(void);

cpu/nrf5x_common/periph/pm.c

@@ -30,7 +30,7 @@
 /* TODO: implement proper pm_off for nRF9160 */
 void pm_off(void)
 {
-#ifndef CPU_FAM_NRF9160
+
 #ifdef CPU_FAM_NRF51
     NRF_POWER->RAMON = 0;
 #else
@@ -40,6 +40,4 @@ void pm_off(void)
     }
 #endif
     NRF_POWER->SYSTEMOFF = 1;
-    while (1) {}
-#endif /* ndef CPU_FAM_NRF9160 */
 }

examples/pulga-low-power-demo/Makefile

@@ -0,0 +1,26 @@
+# name of your application
+APPLICATION = pulga-low-power-demo
+
+# If no BOARD is found in the environment, use this default:
+BOARD ?= native
+
+FEATURES_OPTIONAL += periph_gpio_irq
+FEATURES_OPTIONAL += periph_rtc
+
+USEMODULE += shell
+USEMODULE += shell_commands
+USEMODULE += ztimer
+USEMODULE += ztimer_msec
+USEMODULE += ztimer_usec
+USEMODULE += ztimer_sec
+
+# avoid running Kconfig by default
+SHOULD_RUN_KCONFIG ?=
+
+# This has to be the absolute path to the RIOT base directory:
+RIOTBASE ?= $(CURDIR)/../..
+
+# Change this to 0 show compiler invocation lines by default:
+QUIET ?= 1
+
+include $(RIOTBASE)/Makefile.include

examples/pulga-low-power-demo/README.md

@@ -0,0 +1,3 @@
+examples/pulga-low-power-demo
+================
+See the documentation here: https://docs.google.com/document/d/12KXZuZcm3ZspvcS1gNZgoWsj-F7LGb05mXYUR6eE8TM/edit

examples/pulga-low-power-demo/main.c

@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "periph/pm.h"
+#ifdef MODULE_PERIPH_GPIO
+#include "board.h"
+#include "periph/gpio.h"
+#endif
+#ifdef MODULE_PM_LAYERED
+#include "pm_layered.h"
+#endif
+
+extern int _pm_handler(int argc, char **argv);
+
+#include "shell.h"
+#include "ztimer.h"
+
+#ifndef BTN0_INT_FLANK
+#define BTN0_INT_FLANK  GPIO_RISING
+#endif
+
+#if defined(MODULE_PERIPH_GPIO_IRQ) && defined(BTN0_PIN)
+static void btn_cb(void *ctx)
+{
+    (void) ctx;
+    puts("BTN0 pressed!");
+}
+#endif
+
+int main(void)
+{
+
+    puts("Pulga Low Power!");
+    #ifdef MODULE_ZTIMER
+    puts("ZTIMER definido!");
+    #endif
+    printf("You are running RIOT on a(n) %s board.\n", RIOT_BOARD);
+    printf("This board features a(n) %s MCU.\n", RIOT_MCU);
+
+    printf("This application allows you to test the CPU power management.\n"
+           "The available power modes are 0 - %d. Lower-numbered power modes\n"
+           "save more power, but may require an event/interrupt to wake up\n"
+           "the CPU. Reset the CPU if needed.\n\n\n",
+           PM_NUM_MODES - 1);
+
+#if defined(MODULE_PERIPH_GPIO_IRQ) && defined(BTN0_PIN)
+    puts("using BTN0 as wake-up source");
+    gpio_init_int(BTN0_PIN, BTN0_MODE, BTN0_INT_FLANK, btn_cb, NULL);
+#endif
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
+
+    return 0;
+}