Add Bluetooth examples

Co-authored-by: Peter Harper <77111776+peterharperuk@users.noreply.github.com>

pico_w/wifi/wifi_scan/picow_wifi_scan.c

@@ -0,0 +1,73 @@
+/**
+ * Copyright (c) 2022 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdio.h>
+
+#include "pico/stdlib.h"
+#include "pico/cyw43_arch.h"
+
+static int scan_result(void *env, const cyw43_ev_scan_result_t *result) {
+    if (result) {
+        printf("ssid: %-32s rssi: %4d chan: %3d mac: %02x:%02x:%02x:%02x:%02x:%02x sec: %u\n",
+            result->ssid, result->rssi, result->channel,
+            result->bssid[0], result->bssid[1], result->bssid[2], result->bssid[3], result->bssid[4], result->bssid[5],
+            result->auth_mode);
+    }
+    return 0;
+}
+
+#include "hardware/vreg.h"
+#include "hardware/clocks.h"
+
+int main() {
+    stdio_init_all();
+
+    if (cyw43_arch_init()) {
+        printf("failed to initialise\n");
+        return 1;
+    }
+
+    cyw43_arch_enable_sta_mode();
+
+    absolute_time_t scan_time = nil_time;
+    bool scan_in_progress = false;
+    while(true) {
+        if (absolute_time_diff_us(get_absolute_time(), scan_time) < 0) {
+            if (!scan_in_progress) {
+                cyw43_wifi_scan_options_t scan_options = {0};
+                int err = cyw43_wifi_scan(&cyw43_state, &scan_options, NULL, scan_result);
+                if (err == 0) {
+                    printf("\nPerforming wifi scan\n");
+                    scan_in_progress = true;
+                } else {
+                    printf("Failed to start scan: %d\n", err);
+                    scan_time = make_timeout_time_ms(10000); // wait 10s and scan again
+                }
+            } else if (!cyw43_wifi_scan_active(&cyw43_state)) {
+                scan_time = make_timeout_time_ms(10000); // wait 10s and scan again
+                scan_in_progress = false; 
+            }
+        }
+        // the following #ifdef is only here so this same example can be used in multiple modes;
+        // you do not need it in your code
+#if PICO_CYW43_ARCH_POLL
+        // if you are using pico_cyw43_arch_poll, then you must poll periodically from your
+        // main loop (not from a timer) to check for Wi-Fi driver or lwIP work that needs to be done.
+        cyw43_arch_poll();
+        // you can poll as often as you like, however if you have nothing else to do you can
+        // choose to sleep until either a specified time, or cyw43_arch_poll() has work to do:
+        cyw43_arch_wait_for_work_until(scan_time);
+#else
+        // if you are not using pico_cyw43_arch_poll, then WiFI driver and lwIP work
+        // is done via interrupt in the background. This sleep is just an example of some (blocking)
+        // work you might be doing.
+        sleep_ms(1000);
+#endif
+    }
+
+    cyw43_arch_deinit();
+    return 0;
+}