Show COVID-19 exposure notification statistics

Based on !390 (merged)

Displays how many unique MACs (aka phones) which send exposure notifications have been seen during the last 100 seconds.

It tries to distinguish between Apple and Google devices based on a heuristic mentioned in https://github.com/znuh/microbit-corona-scanner. The user can choose if they want the LEDs and/or the vibration motor to show newly discovered MACs / exposure notifications.

Loosely based on:

• https://github.com/kauzu/CoronaAppDetector
• https://github.com/frankrieger/CoronaAppDetectorM5StickC
• https://github.com/znuh/microbit-corona-scanner

Most of the logic resides in a plain Python script and can be modified by the user as needed.

epicardium/epicardium.h

@@ -2037,7 +2037,7 @@ API(API_USB_CDCACM, int epic_usb_cdcacm(void));
 
 /**
  * Takes a gpio pin specified with the gpio module and transmits
- * the led data. The format `GG:RR:BB` is expected.
+ * the led data. The format ``GG:RR:BB`` is expected.
  *
  * :param uint8_t pin: The gpio pin to be used for data.
  * :param uint8_t * pixels: The buffer, in which the pixel data is stored.
@@ -2223,18 +2223,28 @@ API(API_BLE_GET_COMPARE_VALUE, uint32_t epic_ble_get_compare_value(void));
 API(API_BLE_COMPARE_RESPONSE, void epic_ble_compare_response(bool confirmed));
 
 /**
- * Allow or disallow new bondings to happen
+ * Set the desired mode of the BLE stack.
+ *
+ * There are three allowed modes:
+ *
+ *  - Peripheral which is not bondable (bondable = ``false``, scanner = ``false``).
+ *  - Peripheral which is bondable (bondable = ``true``, scanner = ``false``).
+ *  - Observer which scans for advertisements (bondable = ``false``, scanner = ``true``).
  *
  * By default the card10 will not allow new bondings to be made. New
  * bondings have to explicitly allowed by calling this function.
  *
- * While bonadable the card10 will change its advertisements to
+ * While bondable the card10 will change its advertisements to
  * indicate to scanning hosts that it is available for discovery.
  *
+ * When scanning is active, :c:data:`BLE_EVENT_SCAN_REPORT` events will be sent
+ * and the scan reports can be fetched using :c:func:`epic_ble_get_scan_report`.
+ *
  * When switching applications new bondings are automatically
- * disallowed.
+ * disallowed and scanning is stopped.
  *
  * :param bool bondable: `true` if new bondings should be allowed.
+ * :param bool scanner: `true` if scanning should be turned on.
  *
  * .. versionadded:: 1.16
  */