38 lines
1.2 KiB
Python
38 lines
1.2 KiB
Python
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# Helpers for generating BLE advertising payloads.
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from micropython import const
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import struct
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# Advertising payloads are repeated packets of the following form:
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# 1 byte data length (N + 1)
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# 1 byte type (see constants below)
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# N bytes type-specific data
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_ADV_TYPE_FLAGS = const(0x01)
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_ADV_TYPE_NAME = const(0x09)
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_ADV_TYPE_UUID16_COMPLETE = const(0x3)
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_ADV_TYPE_APPEARANCE = const(0x19)
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# Generate a payload to be passed to gap_advertise(adv_data=...).
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def advertising_payload(limited_disc=False, br_edr=False, name=None, services=None, appearance=0):
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payload = bytearray()
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def _append(adv_type, value):
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nonlocal payload
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payload += struct.pack('BB', len(value) + 1, adv_type) + value
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_append(_ADV_TYPE_FLAGS, struct.pack('B', (0x01 if limited_disc else 0x02) + (0x00 if br_edr else 0x04)))
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if name:
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_append(_ADV_TYPE_NAME, name)
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if services:
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for uuid in services:
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# TODO: Support bluetooth.UUID class.
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_append(_ADV_TYPE_UUID16_COMPLETE, struct.pack('<h', uuid))
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# See org.bluetooth.characteristic.gap.appearance.xml
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_append(_ADV_TYPE_APPEARANCE, struct.pack('<h', appearance))
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return payload
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