add basic ble code

ble_advertising.py

@@ -0,0 +1,93 @@
+# Helpers for generating BLE advertising payloads.
+
+from micropython import const
+import struct
+import bluetooth
+
+# Advertising payloads are repeated packets of the following form:
+#   1 byte data length (N + 1)
+#   1 byte type (see constants below)
+#   N bytes type-specific data
+
+_ADV_TYPE_FLAGS = const(0x01)
+_ADV_TYPE_NAME = const(0x09)
+_ADV_TYPE_UUID16_COMPLETE = const(0x3)
+_ADV_TYPE_UUID32_COMPLETE = const(0x5)
+_ADV_TYPE_UUID128_COMPLETE = const(0x7)
+_ADV_TYPE_UUID16_MORE = const(0x2)
+_ADV_TYPE_UUID32_MORE = const(0x4)
+_ADV_TYPE_UUID128_MORE = const(0x6)
+_ADV_TYPE_APPEARANCE = const(0x19)
+
+
+# Generate a payload to be passed to gap_advertise(adv_data=...).
+def advertising_payload(limited_disc=False, br_edr=False, name=None, services=None, appearance=0):
+    payload = bytearray()
+
+    def _append(adv_type, value):
+        nonlocal payload
+        payload += struct.pack("BB", len(value) + 1, adv_type) + value
+
+    _append(
+        _ADV_TYPE_FLAGS,
+        struct.pack("B", (0x01 if limited_disc else 0x02) + (0x18 if br_edr else 0x04)),
+    )
+
+    if name:
+        _append(_ADV_TYPE_NAME, name)
+
+    if services:
+        for uuid in services:
+            b = bytes(uuid)
+            if len(b) == 2:
+                _append(_ADV_TYPE_UUID16_COMPLETE, b)
+            elif len(b) == 4:
+                _append(_ADV_TYPE_UUID32_COMPLETE, b)
+            elif len(b) == 16:
+                _append(_ADV_TYPE_UUID128_COMPLETE, b)
+
+    # See org.bluetooth.characteristic.gap.appearance.xml
+    if appearance:
+        _append(_ADV_TYPE_APPEARANCE, struct.pack("<h", appearance))
+
+    return payload
+
+
+def decode_field(payload, adv_type):
+    i = 0
+    result = []
+    while i + 1 < len(payload):
+        if payload[i + 1] == adv_type:
+            result.append(payload[i + 2 : i + payload[i] + 1])
+        i += 1 + payload[i]
+    return result
+
+
+def decode_name(payload):
+    n = decode_field(payload, _ADV_TYPE_NAME)
+    return str(n[0], "utf-8") if n else ""
+
+
+def decode_services(payload):
+    services = []
+    for u in decode_field(payload, _ADV_TYPE_UUID16_COMPLETE):
+        services.append(bluetooth.UUID(struct.unpack("<h", u)[0]))
+    for u in decode_field(payload, _ADV_TYPE_UUID32_COMPLETE):
+        services.append(bluetooth.UUID(struct.unpack("<d", u)[0]))
+    for u in decode_field(payload, _ADV_TYPE_UUID128_COMPLETE):
+        services.append(bluetooth.UUID(u))
+    return services
+
+
+def demo():
+    payload = advertising_payload(
+        name="micropython",
+        services=[bluetooth.UUID(0x181A), bluetooth.UUID("6E400001-B5A3-F393-E0A9-E50E24DCCA9E")],
+    )
+    print(payload)
+    print(decode_name(payload))
+    print(decode_services(payload))
+
+
+if __name__ == "__main__":
+    demo()

ble_peripheral.py

@@ -0,0 +1,93 @@
+# This example demonstrates a simple temperature sensor peripheral.
+#
+# The sensor's local value updates every second, and it will notify
+# any connected central every 10 seconds.
+
+import bluetooth
+import random
+import struct
+import time
+from ble_advertising import advertising_payload
+
+from micropython import const
+
+_IRQ_CENTRAL_CONNECT = const(1)
+_IRQ_CENTRAL_DISCONNECT = const(2)
+_IRQ_GATTS_INDICATE_DONE = const(20)
+
+# org.bluetooth.service.environmental_sensing
+_ENV_SENSE_UUID = bluetooth.UUID(0x181A)
+# org.bluetooth.characteristic.temperature
+_TEMP_CHAR = (
+    bluetooth.UUID(0x2A6E),
+    bluetooth.FLAG_READ | bluetooth.FLAG_NOTIFY | bluetooth.FLAG_INDICATE,
+)
+_ENV_SENSE_SERVICE = (
+    _ENV_SENSE_UUID,
+    (_TEMP_CHAR,),
+)
+
+# org.bluetooth.characteristic.gap.appearance.xml
+_ADV_APPEARANCE_GENERIC_THERMOMETER = const(768)
+
+
+class BLETemperature:
+    def __init__(self, ble, name="mpy-temp"):
+        self._ble = ble
+        self._ble.active(True)
+        self._ble.irq(handler=self._irq)
+        ((self._handle,),) = self._ble.gatts_register_services((_ENV_SENSE_SERVICE,))
+        self._connections = set()
+        self._payload = advertising_payload(
+            name=name, services=[_ENV_SENSE_UUID], appearance=_ADV_APPEARANCE_GENERIC_THERMOMETER
+        )
+        self._advertise()
+
+    def _irq(self, event, data):
+        # Track connections so we can send notifications.
+        if event == _IRQ_CENTRAL_CONNECT:
+            conn_handle, _, _ = data
+            self._connections.add(conn_handle)
+        elif event == _IRQ_CENTRAL_DISCONNECT:
+            conn_handle, _, _ = data
+            self._connections.remove(conn_handle)
+            # Start advertising again to allow a new connection.
+            self._advertise()
+        elif event == _IRQ_GATTS_INDICATE_DONE:
+            conn_handle, value_handle, status = data
+
+    def set_temperature(self, temp_deg_c, notify=False, indicate=False):
+        # Data is sint16 in degrees Celsius with a resolution of 0.01 degrees Celsius.
+        # Write the local value, ready for a central to read.
+        self._ble.gatts_write(self._handle, struct.pack("<h", int(temp_deg_c * 100)))
+        if notify or indicate:
+            for conn_handle in self._connections:
+                if notify:
+                    # Notify connected centrals.
+                    self._ble.gatts_notify(conn_handle, self._handle)
+                if indicate:
+                    # Indicate connected centrals.
+                    self._ble.gatts_indicate(conn_handle, self._handle)
+
+    def _advertise(self, interval_us=500000):
+        self._ble.gap_advertise(interval_us, adv_data=self._payload)
+
+
+def demo():
+    ble = bluetooth.BLE()
+    temp = BLETemperature(ble)
+
+    t = 25
+    i = 0
+
+    while True:
+        # Write every second, notify every 10 seconds.
+        i = (i + 1) % 10
+        temp.set_temperature(t, notify=i == 0, indicate=False)
+        # Random walk the temperature.
+        t += random.uniform(-0.5, 0.5)
+        time.sleep_ms(1000)
+
+
+if __name__ == "__main__":
+    demo()

notes.org

@@ -47,9 +47,10 @@ a.get_values()
 #+BEGIN_SRC python
 from machine import Pin
 
-vext = Pin(21, Pin.OUT)
+vext = Pin(21, Pin.OUT, Pin.PULL_HOLD)
 vext.value(0) # Turns ON Vext
 vext.value(1) # Turns OFF Vext
+machine.deep_sleep()
 #+END_SRC
 
 * Wifi Connection Example, outbound requests.
@@ -127,3 +128,8 @@ ESP VEXT -> +Rail
  - [ ] How to detect battery low
  - [[https://github.com/tayfunulu/WiFiManager][WiFiManager]]
 
+
+
+#+BEGIN_SRC python
+
+#+END_SRC