add ULP LP example / update Matter example

examples/espidf-ulp-lp/ulp/main.c

@@ -0,0 +1,64 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+#include <stdint.h>
+#include <stdbool.h>
+#include "sdkconfig.h"
+#include "ulp_lp_core.h"
+#include "ulp_lp_core_utils.h"
+#include "ulp_lp_core_gpio.h"
+#include "ulp_lp_core_interrupts.h"
+#include "ulp_lp_core_print.h"
+#include "riscv/csr.h"
+
+#define DEBOUNCE_INTERVAL_CYCLES 10 // 10 cycles is about 0.625 us at 16 MHz
+
+#define SIMULATED_PULSE_FREQUENCY_HZ 2
+#define SIMULATED_PULSE_DELAY_US (1000000 / SIMULATED_PULSE_FREQUENCY_HZ) / 2
+
+uint32_t pulse_count;
+static uint32_t last_trigger_time_cycles;
+
+void LP_CORE_ISR_ATTR ulp_lp_core_lp_io_intr_handler(void)
+{
+    ulp_lp_core_gpio_clear_intr_status();
+    uint32_t trigger_time_cycles = RV_READ_CSR(mcycle);
+    /* Do some simple debouncing, do not count spurious pulses */
+    if (trigger_time_cycles - last_trigger_time_cycles > DEBOUNCE_INTERVAL_CYCLES) {
+        pulse_count++;
+        last_trigger_time_cycles = trigger_time_cycles;
+    }
+
+    if (pulse_count % CONFIG_EXAMPLE_PULSE_COUNT_WAKEUP_LIMIT == 0) {
+        lp_core_printf("Pulse count: %d, wake-up main CPU\n", pulse_count);
+        ulp_lp_core_wakeup_main_processor();
+    }
+
+}
+
+
+
+int main (void)
+{
+    lp_core_printf("LP Core pulse counter started\n");
+    ulp_lp_core_intr_enable();
+    ulp_lp_core_gpio_intr_enable(CONFIG_EXAMPLE_PULSE_COUNT_PIN, LP_IO_INTR_POSEDGE);
+
+    while(1) {
+
+#if CONFIG_EXAMPLE_PULSE_COUNT_SIMULATE
+        /* No external device connected to generate pulses, we simulate them ourselves instead */
+        ulp_lp_core_delay_us(SIMULATED_PULSE_DELAY_US);
+        ulp_lp_core_gpio_set_level(CONFIG_EXAMPLE_PULSE_COUNT_PIN, 1);
+        ulp_lp_core_delay_us(SIMULATED_PULSE_DELAY_US);
+        ulp_lp_core_gpio_set_level(CONFIG_EXAMPLE_PULSE_COUNT_PIN, 0);
+#else
+        /* Put CPU into a wait state to reduce power consumption while waiting for pulses */
+        ulp_lp_core_wait_for_intr();
+#endif //CONFIG_EXAMPLE_PULSE_COUNT_SIMULATE
+    }
+
+    return 0;
+}