#include "lwip/arch.h"
-extern char wifi_ssid[];
-extern char wifi_pass[];
+/* Wi-Fi credentials */
+extern const char config_wifi_ssid[];
+extern const char config_wifi_pass[];
-extern u16_t tattle_port;
-extern char tattle_server_ip_address[];
+/* Network address of the server to contact */
+extern const char config_tattle_server_ip_address[];
+extern const u16_t config_tattle_port;
-extern u16_t this_tattler_identity;
+/* For distinguishing reports from multiple tattlekey devices. */
+extern const u16_t config_this_tattler_identity;
+
+/* Which GPIO pin is the button connected to?
+ * The button should span this pin and ground, connecting this pin to ground
+ * when pressed.
+ * https://projects.raspberrypi.org/en/projects/introduction-to-the-pico/10
+ * recommends pins 18, 22, or 28. */
+extern const uint config_button_pin;
+
+/* Don't bother reporting each separate button press when it is pressed many
+ * times in short succession. (We also use this to de-bounce. :) */
+extern const u32_t config_minimum_seconds_between_button_presses;
+
+/* Send each report multiple times. */
+extern const uint config_resend_count;
+
+/* These control the size of the per-send-count press queues.
+When the button is pressed more than config_maximum_queue_size times
+within the resend interval, some presses will be reported fewer
+than config_resend_count times. This is usually fine because it's
+the old, longest-delyed, most-redundant reports that get dropped;
+fresh, timely reports of new button presses will not get anywhere near
+config_resend_count in a resend interval because the early resend interals
+are so short. */
+extern const uint config_maximum_queue_size;
+
+/* This is paranoia about unanticipated delays. Setting this to zero
+would pobably be fine, but imposing a minimum queue size is an easy
+safety measure. */
+extern const uint config_minimum_queue_size;
#endif