Add HCI support

Author: dhalbert

adafruit_ble/__init__.py

@@ -156,8 +156,12 @@ class BLERadio:
     It uses this library's `Advertisement` classes and the `BLEConnection` class."""
 
     def __init__(self, adapter=None):
-        if not adapter:
-            adapter = _bleio.adapter
+        if not _bleio.adapter:
+            # Try setting up an onboard HCI BLE adapter.
+            from adafruit_ble import hci  # pylint: disable=import-outside-toplevel
+
+            adapter = hci.create_adapter()
+            _bleio.set_adapter(adapter)
         self._adapter = adapter
         self._current_advertisement = None
         self._connection_cache = {}

adafruit_ble/hci.py

@@ -0,0 +1,113 @@
+# The MIT License (MIT)
+#
+# Copyright (c) 2020 Dan Halbert for Adafruit Industries
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+"""
+Sets up an on-board HCI BLE adapter.
+"""
+
+import time
+
+import board
+import busio
+import digitalio
+import _bleio
+
+
+def create_adapter_esp32_hci(
+    *,
+    esp_reset=board.ESP_RESET,
+    esp_gpio0=board.ESP_GPIO0,
+    esp_busy=board.ESP_BUSY,
+    esp_cs=board.ESP_CS,
+    esp_tx=board.ESP_TX,
+    esp_rx=board.ESP_RX,
+    reset_high=False,
+    debug=False
+):
+    """Do ESP32-specific HCI adapter initialization."""
+
+    reset = digitalio.DigitalInOut(esp_reset)
+    reset.switch_to_output(not reset_high)
+
+    gpio0_and_rts = digitalio.DigitalInOut(esp_gpio0)
+    cts = digitalio.DigitalInOut(esp_busy)
+    chip_select = digitalio.DigitalInOut(esp_cs)
+
+    uart = busio.UART(
+        esp_tx, esp_rx, baudrate=115200, timeout=0, receiver_buffer_size=512
+    )
+
+    # Boot ESP32 from SPI flash.
+    gpio0_and_rts.switch_to_output(True)
+
+    # Choose Bluetooth mode.
+    chip_select.switch_to_output(False)
+
+    # Start reset
+    reset.value = reset_high
+    time.sleep(0.1)
+
+    # Release reset and wait for startup and startup message.
+    reset.value = not reset_high
+    time.sleep(1.0)
+
+    startup_message = b""
+    while uart.in_waiting:  # pylint: disable=no-member
+        more = uart.read()
+        if more:
+            startup_message += more
+
+    if not startup_message:
+        raise _bleio.BluetoothError(
+            "HCI adapter did not respond with a startup message"
+        )
+
+    if debug:
+        try:
+            print(startup_message.decode("utf-8"))
+        except UnicodeError:
+            raise _bleio.BluetoothError("Garbled HCI startup message")
+
+    # pylint: disable=no-member
+    return _bleio.Adapter(uart=uart, rts=gpio0_and_rts, cts=cts)
+
+
+def create_adapter(debug=False):
+    """Determine whether an on-board HCI adapter is available, and initialize it.
+    Currently only ESP32 co-processors are supported.
+    """
+    # See if all the pins we need for an ESP32 HCI adapter are available.
+    if all(
+        pin in dir(board)
+        for pin in ("ESP_RESET", "ESP_GPIO0", "ESP_BUSY", "ESP_CS", "ESP_TX", "ESP_RX")
+    ):
+        return create_adapter_esp32_hci(
+            esp_reset=board.ESP_RESET,
+            esp_gpio0=board.ESP_GPIO0,
+            esp_busy=board.ESP_BUSY,
+            esp_cs=board.ESP_CS,
+            esp_tx=board.ESP_TX,
+            esp_rx=board.ESP_RX,
+            reset_high=False,
+            debug=debug,
+        )
+    else:
+        raise _bleio.BluetoothError("ESP32 HCI adapter pins not available")