Initial Release

clocks/hello_resus/hello_resus.c

@@ -0,0 +1,48 @@
+/**
+ * Copyright (c) 2021 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+#include "hardware/clocks.h"
+#include "hardware/pll.h"
+
+volatile bool seen_resus;
+
+void resus_callback(void) {
+    // Reconfigure PLL sys back to the default state of 1500 / 6 / 2 = 125MHz
+    pll_init(pll_sys, 1, 1500 * MHZ, 6, 2);
+
+    // CLK SYS = PLL SYS (125MHz) / 1 = 125MHz
+    clock_configure(clk_sys,
+                    CLOCKS_CLK_SYS_CTRL_SRC_VALUE_CLKSRC_CLK_SYS_AUX,
+                    CLOCKS_CLK_SYS_CTRL_AUXSRC_VALUE_CLKSRC_PLL_SYS,
+                    125 * MHZ,
+                    125 * MHZ);
+
+    // Reconfigure uart as clocks have changed
+    stdio_init_all();
+    printf("Resus event fired\n");
+
+    // Wait for uart output to finish
+    uart_default_tx_wait_blocking();
+
+    seen_resus = true;
+}
+
+int main() {
+    stdio_init_all();
+    printf("Hello resus\n");
+
+    seen_resus = false;
+
+    clocks_enable_resus(&resus_callback);
+    // Break PLL sys
+    pll_deinit(pll_sys);
+
+    while(!seen_resus);
+
+    return 0;
+}